Author Topic: Bronze Swing Arm Bushings For C5?  (Read 25945 times)

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gashousegorilla

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on: June 30, 2010, 04:13:27 am
Does anyone know if they are available, if so where can they be sourced?
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Ice

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Reply #1 on: June 30, 2010, 10:15:35 am
I should think that they would be easy enough to have turned from Oilite bronze stock by any high school machine shop student for the price of a pizza.

 I have wondered about using needle roller bearing myself.
IIRC Suzuki's GS (ca. 1978) was the first mass produced street bike to have needle rollers in the swinging arm. Oh what a superb machine.
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gashousegorilla

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Reply #2 on: June 30, 2010, 03:15:51 pm
I should think that they would be easy enough to have turned from Oilite bronze stock by any high school machine shop student for the price of a pizza.

 I have wondered about using needle roller bearing myself.
IIRC Suzuki's GS (ca. 1978) was the first mass produced street bike to have needle rollers in the swinging arm. Oh what a superb machine.

  Oh Yea needle bearings would be nice :P.  But I think bronze bushings would be pushing it. And yes the good old days of shop class. But  I think where showing our age Ice. There no more machine shop classes, wood shop classes , elec shop classes, automotive, auto body,etc. At least  not like it use to be. Try to get a kid now a days to create something with their hands other than a text message. It's just as well,as there would probably be no jobs out their anyway. It's getting hard to find a decent tool/die shop, there all closing up,at least in my area.
  Maybe there's a Machinist out there, that would be willing to make a run of them if there's enough of us showing interest?
« Last Edit: June 30, 2010, 03:27:32 pm by gashousegorilla »
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ace.cafe

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Reply #3 on: June 30, 2010, 03:55:29 pm
If the OEM rubber bushes are installed anything like they are in the Iron Barrel models, it isn't so much about what new ones to put in, but more about how to get the OEM ones out.
Most people report having  a very hard time removing the OEM bushes in the Iron Barrel models.
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gashousegorilla

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Reply #4 on: July 02, 2010, 03:43:52 am
OK, I may have a line on a place that may have them(Mcmaster-carr). Before I Take apart the rear end, and put the bike out of commission,does anyone have the dimensions of the stock Bushings?
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Ice

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Reply #5 on: July 02, 2010, 10:42:27 am
IMHO Mcmaster Carr is a top notch company to deal with.

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shappers

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Reply #6 on: July 02, 2010, 02:38:23 pm
Hi Hi, another source may be Hitchcock in the UK.

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ScooterBob

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Reply #7 on: July 02, 2010, 02:48:25 pm
IMHO Mcmaster Carr is a top notch company to deal with.



Top notch, INDEED! They have everything from 310 stainless socket head fasteners to a brand new leather drive belt for my sewing machine ..... you just gotta LOVE that!!
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SSR

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Reply #8 on: July 02, 2010, 05:26:43 pm
Can anybody confirm if the bronze bush will need grease for lubrication and if yes, how can that be done? Is it by putting a nipple grease feed on the shaft bolt?


ScooterBob

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Reply #9 on: July 02, 2010, 05:41:26 pm
Can anybody confirm if the bronze bush will need grease for lubrication and if yes, how can that be done? Is it by putting a nipple grease feed on the shaft bolt?

Of COURSE the bush will need lubrication! gun-drilling the shaft bolt - and knurling it for grease distribution would be a good thing - but you COULD add a couple of grease fittings to the pivot lugs on the swing arm as well and keep the bolt solid.
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gashousegorilla

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Reply #10 on: July 02, 2010, 05:52:55 pm
Ya, Mcmaster-Carr is awsome. A gear head Nirvana.
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gashousegorilla

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Reply #11 on: July 02, 2010, 06:02:02 pm
Of COURSE the bush will need lubrication! gun-drilling the shaft bolt - and knurling it for grease distribution would be a good thing - but you COULD add a couple of grease fittings to the pivot lugs on the swing arm as well and keep the bolt solid.
  Scooterbob has it wright, I'm planing on doing the latter, If I can get some internally groved bushings.
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ScooterBob

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Reply #12 on: July 02, 2010, 06:10:27 pm
  Scooterbob has it wright, I'm planing on doing the latter, If I can get some internally groved bushings.

I'm guessing that you'd want to braze weld a couple of lugs on the swingarm to have something to screw your grease fittings into ..... you COULD even get uber clever and plumb them together and make one easy-to-reach fitting ...... Hmmmmmm .......
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SSR

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Reply #13 on: July 02, 2010, 06:12:37 pm
Of COURSE the bush will need lubrication! gun-drilling the shaft bolt - and knurling it for grease distribution would be a good thing - but you COULD add a couple of grease fittings to the pivot lugs on the swing arm as well and keep the bolt solid.

Thanks ScooterBob. Just another thing I need to know, Should I get  spiral shaped groove inside the bush or some holes from inside the bush to keep some amount of lubrication?



gashousegorilla

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Reply #14 on: July 02, 2010, 08:05:45 pm
I'm guessing that you'd want to braze weld a couple of lugs on the swingarm to have something to screw your grease fittings into ..... you COULD even get uber clever and plumb them together and make one easy-to-reach fitting ...... Hmmmmmm .......
Stop Scooterbob, your making me drool :P. Not sure yet how I'll configue the lubrication system, I'll see when I get the swing arm out. But I am thinking of something along the lines of a honda  cb, with grooved Bushings, greese fitting on bottom of swing arm, tapped into pivot bolt Chamber, Don't know yet, but will see.
  I also want to gusset/ reinforce the swing arm where the side tubes meet the cross tube. In an arch shape. Like somthing you would see on other bike's, honda cb's, harley sporters, etc. I'm looking to eliminate the side to side flex in the rear end ,as you could probably guess.
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Ducati Scotty

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Reply #15 on: July 02, 2010, 09:46:33 pm
That's what I was thinking, groove the bushing, drill and tap it for the greas fitting, drill a hole to fit it, and have the bushing and grease fitting screw together and 'sandwich' the steel of the swingarm.

On a less intensive path, couldn't you just make urethane bushing instead of bronze?  Gotta be easier to shape and less play but not none, doesn't transmit all the stress to the swingarm.  Of course, they need to be lubed too or they stick and squeak.  Rubber is more forgiving.

Scott


gashousegorilla

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Reply #16 on: July 02, 2010, 10:16:10 pm
That's what I was thinking, groove the bushing, drill and tap it for the greas fitting, drill a hole to fit it, and have the bushing and grease fitting screw together and 'sandwich' the steel of the swingarm.

On a less intensive path, couldn't you just make urethane bushing instead of bronze?  Gotta be easier to shape and less play but not none, doesn't transmit all the stress to the swingarm.  Of course, they need to be lubed too or they stick and squeak.  Rubber is more forgiving.

Scott

   Some very good ideas Scotty.  Urethane bushings though? Tell me more.
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Ducati Scotty

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Reply #17 on: July 02, 2010, 10:56:22 pm
Lots of things in autos and motos are linked with rubber bushings: shock mounts, sway bar mounts, engine mounts, shift linkages.  This is generally done to provide a certain amount of flex and isolate vibration to the driver & passengers.  It also adds a certain amount of slop which may be good for comfort but bad for performance.  In high performance and race vehicles these rubber bits are often replaced with urethane, the stuff skateboard wheels are made of.  It has some flex but much less than rubber.  This tightens things up for better performance and is great BUT while rubber can work while dry some urethane things need to be greased regularly to work.

Some things are fine without grease.  For instance, a sway bar mount doesn't need to move much it's just a flexible connection.  No worries on grease.  Something like a swingarm bushing, that's moving.  It will need grease to keep doing so.  Which means you'd need to disassemble and lube regularly or get a fitting connected.

Scott


gashousegorilla

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Reply #18 on: July 03, 2010, 04:47:41 am
Thanks Scotty, I'm gonna do some more research on Urethane to see if there's any bushings available . According to the service manual , the bushings in the c5 are plastic, not rubber, I would imagine plastic would be a harder material then urethane,no? Well it's all speculation until I pull out the swing arm and see what I got. I'll let you know.
Thanks, Dan. 
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Ducati Scotty

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Reply #19 on: July 03, 2010, 07:30:58 am
Yup, less flex than rubber and may not need regular lubrication.

Scott


Ice

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Reply #20 on: July 03, 2010, 11:33:00 am
« Last Edit: July 03, 2010, 11:37:23 am by Ice »
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ace.cafe

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Reply #21 on: July 03, 2010, 12:43:27 pm
My estimation would be that if they are plastic, they are already something like polyurethane, and I doubt that any real improvement would be found with bronze.
It might just be best to leave them as they are.
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SSR

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Reply #22 on: July 03, 2010, 03:01:30 pm
My estimation would be that if they are plastic, they are already something like polyurethane, and I doubt that any real improvement would be found with bronze.
It might just be best to leave them as they are.


Any other way of reducing side ways or X movement of swing arm?


Ducati Scotty

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Reply #23 on: July 03, 2010, 03:53:02 pm
Molybdenum disulphide filled Nylon 6/6  ;D

http://www.mcmaster.com/#nylon/=7sqjej

or 6/12

http://www.mcmaster.com/#nylon/=7sqlfu

And you can probably cut them on an inexpensive wood lathe.

Of course they might not be any better Ace.  Don't rain on the parade.  We're building stuff!  ;)  Besides, these might make a nice replacement for the older rubber bushings but with less need for lubrication than a set in bronze.

Scott


gashousegorilla

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Reply #24 on: July 03, 2010, 05:29:06 pm
I'm off to the garage boy's, will see what I got. If there plastic, well then gusseting becomes more likely.will see. I'll give an update latter. Thanks.
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clubman

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Reply #25 on: July 03, 2010, 09:31:11 pm
Any other way of reducing side ways or X movement of swing arm?

I vaguely recall reading elsewhere of the early failure of these plastic bushings. Glad to say I've not had any problem to date but are there any dealers here that can give us a perspective?


ace.cafe

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Reply #26 on: July 03, 2010, 10:58:51 pm
Okay, I like building stuff too!

In the spirit of innovation, I've thought about this before, and will add my 2 cents..
If you go to an AutoZone or someplace like that, you'll find sway-bar bushings and other suspension bushings made of polyurethane, which are made for sports applications.
They usually come in a kit, which may have more bushings than you need, and perhaps not all the correct size.
But, you can drill out the center holes if they are smaller, and you can turn down the outer diameter if they are large. If the center hole is too big, you can probably find a metal sleeve that you can press into it, to make it the right size to fit the shaft.
You can end up with the right size after you are done.
I would make them a little big on the O.D. and push them in tight.
I've seen bushings at AutoZone which would work in an Iron Barrel swing-arm with modifications like I described, for under twenty bucks, and you'd have extras left over.

Cheap, available, and easy to modify, and the material is made for the purpose.

I think a little bit of "give" is good, and it won't move noticeably, and should do.
I don't particularly like solid metal bushings  or needle bearings because I think they are harsh, and transmit alot of vibration.

My 2 cents.
« Last Edit: July 03, 2010, 11:02:04 pm by ace.cafe »
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enfield freddy

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Reply #27 on: July 03, 2010, 11:33:33 pm
Tom , I recently sorted a 55 frame out for another british bullatier (dan ford), the frame was old and the paint was tired



after having it chemicly cleaned , you can see all the braizing on it?



I then got it proffesdsionally painted for him

the earlier UK bikes used a bronze bush settup at the back with pleanty of grease nipples , I replaced the shaft as it was a bit "dull" , what a nice setup!

enfield thought proper in those days , the outer large nuts were made in such a way that a screw was placed in the frame and locked the nuts , the quality of the frame inc the headstock , made the indian frame look like a "photocopy" read from a distance ,,,

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ace.cafe

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Reply #28 on: July 03, 2010, 11:46:07 pm
Tom , I recently sorted a 55 frame out for another british bullatier (dan ford), the frame was old and the paint was tired



after having it chemicly cleaned , you can see all the braizing on it?



I then got it proffesdsionally painted for him

the earlier UK bikes used a bronze bush settup at the back with pleanty of grease nipples , I replaced the shaft as it was a bit "dull" , what a nice setup!

enfield thought proper in those days , the outer large nuts were made in such a way that a screw was placed in the frame and locked the nuts , the quality of the frame inc the headstock , made the indian frame look like a "photocopy" read from a distance ,,,



That looks nice Alan!
So, they did the swing arm nut like they do the crankpin nut on the flywheels, with a small screw alongside it?

Does Dan feel any difference in ride with the bronze bushings in there?
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enfield freddy

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Reply #29 on: July 04, 2010, 12:02:52 am
tom the nuts are like nuts that take a "c" spanner" , with cuttouts , and a small screw (2ba) is screwed into the frame in a proper threaded hole , the holes in the frame are larger than the inyun one , there is a stepped washer (thrust washer) that alignes it , on the inside and comes thru the larger holes in the frame ,look at the headstock , no silly triangular plate wielded in!

tom , I think you know dan from the yahhoo sites , his bike seems to win "best of shows" in the UK , being a 2005 model but looking like a 50s bike (nice bloke!)

here you go , ready for rebuild



now having ridden a few "full blown racers" , some of which have exceeded 45bhp (for sprint racing < 1/2 mile>)  I prfer the older pre 55 frame (but english  made) as opossed the the later 55+ bullet frame , the idiots sold it to india and decided to use a "crusader" type frame  WRONG , the older frame handles better than thelater one ,

dunno about dans frame , but i,m sue he will reply ?

« Last Edit: July 04, 2010, 12:15:04 am by enfield freddy »
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gashousegorilla

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Reply #30 on: July 04, 2010, 12:33:56 am
     OK, the swing arm is out, pretty simple affair as you could imagine. The flex in the swing arm becomes apparent as soon as you remove the axle nut.It's a simple Japanese arch type design,without any reinforcement. The swing arm springs open about 3-4 mm.The bushings are made of a white plastic material. The exposed ends of which,on either side appear to have been reamed with hamster teeth, where the spacer slides through. The spacer has no movement, the swing arm pivots on the pivot bolt inside the spacer, metal to metal, bone dry. There is a .5-1.0 mm 's worth of slop inside the spacer/pivot bolt. Yikes!!!  No wonder my high speed highway jaunts are a scary affair. It's like a Ducks ass after he gets out of the pond. :D. Time for a redesign Boys? 
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enfield freddy

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Reply #31 on: July 04, 2010, 12:38:04 am
     OK, the swing arm is out, pretty simple affair as you could imagine. The flex in the swing arm becomes apparent as soon as you remove the axle nut.It's a simple Japanese arch type design,without any reinforcement. The swing arm springs open about 3-4 mm.The bushings are made of a white plastic material. The exposed ends of which,on either side appear to have been reamed with hamster teeth, where the spacer slides through. The spacer has no movement, the swing arm pivots on the pivot bolt inside the spacer, metal to metal, bone dry. There is a .5-1.0 mm 's worth of slop inside the spacer/pivot bolt. Yikes!!!  No wonder my high speed highway jaunts are a scary affair. It's like a Ducks ass after he gets out of the pond. :D. Time for a redesign Boys? 

 look back in history , (as posted above) when enfield (great britain) made proper frames , rather than "photocopied" frames?
look at the old phosper bronze settup , seemed to work for over 50 yrs?
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gashousegorilla

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Reply #32 on: July 04, 2010, 01:25:32 am
look back in history , (as posted above) when enfield (great britain) made proper frames , rather than "photocopied" frames?
look at the old phosper bronze settup , seemed to work for over 50 yrs?
  Agreed Freddy. hard to beat an old Brit bike for there exquisite handling.Look at the Feather Bed and how versatile  it is.Oh well I think I can get this sorted. 
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chinoy

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Reply #33 on: July 05, 2010, 06:41:38 am
glad to see your making progress.
Like I said in the PM its not the front end.

In 1971 Yamaha Introduced the Poly Urathane Bushes on the RD in 1972 people had shifted to Bronze bushings. We have been making and exporting these for over a decade.

Fixing the bronze swing arm bushings or the rollers I mentioned is a band aid fix at best.
Its not going to cure your stability issues. Instead of becoming unsafe at 100 kmph it now do it at 105 kmph.

For that your going to need a new swing arm.
Since you have it off.
Can you post the measurements i.e. how wide is the head stock.
I can then see what other more modern bikes we have here which have better swing arms can be bolted on.
Most of the other bikes here are mopeds i.e. 100-150 cc but they have better build swing arms. Which hold up even on 50 BHP RDs.


gashousegorilla

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Reply #34 on: July 05, 2010, 07:20:49 pm
glad to see your making progress.
Like I said in the PM its not the front end.

In 1971 Yamaha Introduced the Poly Urathane Bushes on the RD in 1972 people had shifted to Bronze bushings. We have been making and exporting these for over a decade.

Fixing the bronze swing arm bushings or the rollers I mentioned is a band aid fix at best.
Its not going to cure your stability issues. Instead of becoming unsafe at 100 kmph it now do it at 105 kmph.

For that your going to need a new swing arm.
Since you have it off.
Can you post the measurements i.e. how wide is the head stock.
I can then see what other more modern bikes we have here which have better swing arms can be bolted on.
Most of the other bikes here are mopeds i.e. 100-150 cc but they have better build swing arms. Which hold up even on 50 HP RDs.

OK, here's some pics. I want all to realize that I started this thread with the honest intention of making a very good and affordable product better. One witch is more stable at Highway speeds. I enjoy this bike very much, and it's below highway speed stability and handling is excellent. It's fit and finish, overall quality of manufacture is pretty good. So please lets knock our heads together and come up with a solution. And please lets not get defensive,and stay positive. I do not believe this is an issue with just my Bike. I personally believe it is a week swing arm design, One witch can not handle the The new UCE , very torquey engine, witch can achieve speeds of around 80 mph in it's stock configuration. The instability of my Bike starts at around 55-60 mph, and progressively get worse as the speed increases. I have been through all of the usual suspects , alignment, stearing headplay , Tire balancing . rim trueing, wheel bearings' etc, etc,etc. The Problem with my bike is in the rear.
 You can see in the pic, I have a comparison of a 72' Honda cb350 verses the 09' c5 swing arms. Notice the extra support on the cb's swing arm near the pivot area. I am using this example,because it is what I have handy, and for no other reason. I believe this is where the problem lye's.
 So come on guy's lets all of find a solution. May be I'm wrong? Maybe it's just my Bike or swing arm? But I don't think so. Go out to your c5, strattle the bike with both feet on the ground, both hands on the bars, look over your shoulder and give the handlebars a shake, see if there is any excessive side to side flex. Now try it with one of your other bikes.
 Thanks,Dan.
An thaibhsí atá rattling ag an doras agus tá sé an diabhal sa chathaoir.


gashousegorilla

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Reply #35 on: July 05, 2010, 07:34:51 pm
Sorry Guys other pics are not uploading, I guess I have to make them smaller?
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ace.cafe

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Reply #36 on: July 05, 2010, 08:18:08 pm
Well, the swing arm on the UCE bikes is longer than the older Bullets.
Perhaps that's an issue.

If there's room for some gusseting or bracing, that might help.

I know that on the older Bullets, they are stable at over 100mph, even with rubber bushes in there. And they can carve a turn quite well, too.

Maybe the longer arm is showing some flex?
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gashousegorilla

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Reply #37 on: July 05, 2010, 09:06:59 pm
Well, the swing arm on the UCE bikes is longer than the older Bullets.
Perhaps that's an issue.

If there's room for some gusseting or bracing, that might help.

I know that on the older Bullets, they are stable at over 100mph, even with rubber bushes in there. And they can carve a turn quite well, too.

Maybe the longer arm is showing some flex?
Yea Ace, that may be the issue,you can push in on the swing arm at the end like Susan sommers on her exercise machine ::) The c5 measures about 18 1/8 inch along side tube,from it's connection to the cross tube(pivot Tube),to the end, on the inside. Sorry but I have a great pic ,but can't figure out how to post it. And yes there is room for bracing, Which is not a big deal. But What size and exactly where is what I"m contemplating. Don't want to screw it up, I only have one to mess with.
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Ducati Scotty

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Reply #38 on: July 05, 2010, 09:31:55 pm
Let's back up just a bit.  I'm of the opinion that improving the swingarm and the pivot point for it would both be good, but maybe there's a simpler solution.

It's been noted here many times that the G5 is a little more stable at speed than the C5 because all of the geometry between the two models is the same EXCEPT the wheel size.  The G5 runs 19" wheels front and back and the C5 has 18" wheels front and back.  This gives the C5 slightly less trail.  Recently there was a note in a thread from Ace or Scooter Bob (can't remember which) that they had put a 19" wheel on the front of a C5 and it made it noticeably more stable at speed. 

You could probably try this out in an afternoon if there's someone nearby with a G5 that would loan you their front wheel for a few hours.  Or, if you've got your rear shocks cranked up on preload just set them to the lowest setting.  That will dip the rear a little lower which will also give you a little more trail (also more rake).  Heck, even leaning back might make a difference, though maybe not the best idea when getting to the upper limits of speed ;)

While the C5 is a really cool bike the 18" wheels on that frame make it less suitable for the speeds the engine will deliver.

Thoughts?

Scott


gashousegorilla

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Reply #39 on: July 05, 2010, 10:58:28 pm
I agree Scott that this bike is in need of a nineteen inch wheel, but in the thread you are speaking of, it was really never tested for any extent.  My bike flexes excessively in the rear at highway speeds. It's readily apparent. A nineteen will help, but I think it only will mask the problem a bit. I am certainly willing to try, is there any G-5 owners out there in the NY/ NJ area who can help out?  As for my dealer? He is no longer a Dealer for reasons unrelated. I'm hesitant to drop the coin and go through the labor of the conversion, only to be frustrated.
 As for the suspension adjustments you mention, they have been tried. The bike only stabilizes when tucking in, leaning forward, and reducing speed . In other words, holding the front end steady, while the rear end  stabilizes. This is can be brought on  by any turbulence, the higher the speed, the less turbulence it takes to induce.  A  small bump in the road, a gust of wind, a passing truck,etc. At speeds below say 50mph, it's not an issue. And think about it, a  couple of minor suspension adjustments or 1" wheel size difference should not make a drastic effect at 55-60 mph. If it does.............
  Stability on a bike should increase with straight line speed, unless the geometry is way off, or there is another factor upsetting the straightness if you will. I don't think the geometry is that far off.
« Last Edit: July 05, 2010, 11:09:14 pm by gashousegorilla »
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Reply #40 on: July 05, 2010, 11:10:54 pm
I ride my C5 55-60 all the time, I've never had any problem like this. Try a 4.00x18 on the rear and a 3.25x18 on the front, they are quite a bit taller than the stock C5 tires and might give you what you need.
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gashousegorilla

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Reply #41 on: July 05, 2010, 11:54:18 pm
Thanks r80rt, it's something to think about. Have you tried this tire swap and if so why? The Avon road riders that come stock on the c5 are an excellent tire. Maybe you used one with a higher side wall?  Witch brand and metric size did you use?
 Thanks ,Dan
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Reply #42 on: July 06, 2010, 12:04:17 am
I haven't worn the original tires out yet, when I replace the front I'll try a 3.00 or 3.25 they should be nearly as tall as a 19, I'll keep the low profile rear because I'm short. But to be honest my bike handles fine I just don't care for low profile front tires. I'm looking at the pirelli MT66 3.00x18 for the front.
« Last Edit: July 06, 2010, 12:08:09 am by r80rt »
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gashousegorilla

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Reply #43 on: July 06, 2010, 12:10:37 am
I haven't worn the original tires out yet, when I replace the front I'll try a 3.00 or 3.25 they should be nearly as tall as a 19, I'll keep the low profile rear because I'm short. But to be honest my bike handles fine I just don't care for low profile front tires. I'm looking at the pirelli MT66 3.00x18 for the front.
Gotcha, certainly cheaper and easier than a 19" conversion.
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r80rt

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Reply #44 on: July 06, 2010, 12:12:56 am
Well, it's something to think about, I know a taller front tire would be good.
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Ducati Scotty

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Reply #45 on: July 06, 2010, 01:09:47 am
Stability on a bike should increase with straight line speed, unless the geometry is way off, or there is another factor upsetting the straightness if you will. I don't think the geometry is that far off.

The geometry doesn't need to be off, just inadequate for the speed.  Long trail, better high speed, short trail, easier flickability into turns.  All the REs are short trail bikes.  This is also the reason choppers got long forks. The increased trail was much better for straight line stability at high speeds.

You would be surprised how little of a difference you need to make to notice.  It's common for some sport bikes to move the fork tubes up in the triple clamps a little bit.  1/4" can make a bike amazingly better at turning, sometimes even dangerously so since high speed stability suffers.

All that said, changing tires is a much cheaper way to go about things.  Again, tire sizes and profiles can make a huge difference.  And as mentioned, tires are cheaper than wheel swaps.

Again, I don't think you should necessarily stop moving forward with the bushings, just putting these options in too.

Scott


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Reply #46 on: July 06, 2010, 01:55:56 am
The geometry doesn't need to be off, just inadequate for the speed.  Long trail, better high speed, short trail, easier flickability into turns.  All the REs are short trail bikes.  This is also the reason choppers got long forks. The increased trail was much better for straight line stability at high speeds.

You would be surprised how little of a difference you need to make to notice.  It's common for some sport bikes to move the fork tubes up in the triple clamps a little bit.  1/4" can make a bike amazingly better at turning, sometimes even dangerously so since high speed stability suffers.

All that said, changing tires is a much cheaper way to go about things.  Again, tire sizes and profiles can make a huge difference.  And as mentioned, tires are cheaper than wheel swaps.

Again, I don't think you should necessarily stop moving forward with the bushings, just putting these options in too.

Scott
All good points Scotty, and well taken.I do believe the answer is going to lye with a combination of all of these thoughts. I'm having an Engineer friend of mine over to have a look, who by the way has a sweet cb500t , that I work on, and get his opinion.
 will get it.  Dan.
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Reply #47 on: July 08, 2010, 04:42:25 am
OK,after consulting with my Engineer friend and he running some numbers,had the following suggestions, to be tried incrementally.
 The swing arm bushings are adequate, but pivot bolt/spacer need lubrication. No da Right?
  Gusseting of swing arm, in area of the intersection of pivot tube and side tubes, in an arch shape with 10 gauge steel, increasing swing arm rigidity by a factor of 2.This may make the swing are too stiff, and eliminates almost all of the flex. Also more labor for me.
  Option two is to cross brace swing arm, about 2 1/4" down from pivot tube, between side tubes with equal or greater size pipe.(1" Black Pipe).This works out to be about a 30% reduction in rigidity from above, which may be enough. Less work for me.
   He also had an interesting thought about the front wheel. Leave the stock 18" rim and low profile tire, but add 4 crimp on spoke weights, directly across from each other, spaced evenly around  rim.Weights of maybe 3/4 oz or 1 oz. Then balance wheel with a 5th,of what ever size needed. This will give the front wheel more mass, and more difficult to upset at higher speeds,but retaining most of the maneuverability of the smaller wheel. Pretty cool thought Huh?  Cheaper than a new tire/ rim.
 Sparks will be flying in the Garage tomorrow Boys, I'll let you know. Dan
        
« Last Edit: July 08, 2010, 02:55:47 pm by gashousegorilla »
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Ducati Scotty

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Reply #48 on: July 08, 2010, 03:46:55 pm
The weights?  I dunno.  The tire itself already weighs much more and is further out on the rim than weights would be providing for higher angular momentum.  And you think your problem is at the rear.  Will it really matter?  I've also never seen anyone make a motorcycle wheel heavier for better performance or handling.

All the other stuff sounds really good.

Scott


gashousegorilla

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Reply #49 on: July 08, 2010, 05:59:14 pm
The weights?  I dunno.  The tire itself already weighs much more and is further out on the rim than weights would be providing for higher angular momentum.  And you think your problem is at the rear.  Will it really matter?  I've also never seen anyone make a motorcycle wheel heavier for better performance or handling.

All the other stuff sounds really good.

Scott
Yea, I don't know either Scott, but as I said in my earlier post , it may be both. And it's all theory until tried.
 With the weights he went on about Inertia, gyro scopic forces, body's in motion with greater mass/ weight being harder to upset from that motion.Basically it's like simulating a larger wheel, with it's weight characteristics, not it's size. I know, a little "Rube Goldburgish" What the heck, its a couple of doller experiment.
 I guess with alloy wheels, what your trying to achieve is a power to weight reduction, at least in part. also with alloy you can have wider rim, for less weight then steel. Steel would off set any gains.
 I think adding a few ounces of weight in not a big deal to this very light Bike, and who knows? it may help. WOW !! it's getting deep Huh?
Dan.
« Last Edit: July 08, 2010, 06:28:43 pm by gashousegorilla »
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Ducati Scotty

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Reply #50 on: July 08, 2010, 07:19:04 pm
Certainly worth trying, but if I recall correctly, weight contributes to angular momentum and the gyroscopic vector in proportion to the square of it's distance from the center of rotation.  So just buying a heavier style of tire would be way more effective than weights since the outer heavy skin of the tire weighs more and is further from the center.  Also, making wheels lighter is generally done because while it takes a linear amount of force to accelerate the chassis in a straight line, accelerating the wheels in rotation up to the same speed takes roughly 4 times the amount of energy.  I think there's another formula with a squared factor in it but I don't recall if offhand.  Also, the gyroscopic force created by a wheel makes the force required to turn the bars grow exponentially with speed.  You can use the mildest counter steering inputs to great effect at slow speeds but racers really need to work to turn a bike that's moving at 150-200mph.

There have really been vast improvments in the understanding of how and why a motorcycles handle the way they do in the last 20 years.  Fork rake, wheel weight, wheel diameter, and so many other things play a part but trail is really one of the strongest factors.  In fact a bicycle or motorcyle stays upright on it's own mostly because of trail, not gyroscopics.  I believe there was an experimental rig built with counter rotating gyros to cancel the gryo force of the wheels, still totally ridable because of trail.  Without cutting and rewelding the frame or making big fork mods it's hard to modify trail.  The easiest thing to do is change tires or suspension heights which may have a smaller effect but still has some.

All that said, there are things to keep in mind.  Physics is often non-intuitve.  This is a theoretical discussion of a single element that may or may not be the cause of a real motor bike that is a complex collection of moving systems.  Sometimes something that makes no sense in theory fixes a problem.  You could probably get to the root of why but it's often not worth figuring out.

Wow!  And you thought it was deep before!

As you said, a few dollars to see what happens.  I just have an ingrained need to know why.  Ignore me at your leisure ;)

Scott


gashousegorilla

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Reply #51 on: July 08, 2010, 07:34:55 pm
Certainly worth trying, but if I recall correctly, weight contributes to angular momentum and the gyroscopic vector in proportion to the square of it's distance from the center of rotation.  So just buying a heavier style of tire would be way more effective than weights since the outer heavy skin of the tire weighs more and is further from the center.  Also, making wheels lighter is generally done because while it takes a linear amount of force to accelerate the chassis in a straight line, accelerating the wheels in rotation up to the same speed takes roughly 4 times the amount of energy.  I think there's another formula with a squared factor in it but I don't recall if offhand.  Also, the gyroscopic force created by a wheel makes the force required to turn the bars grow exponentially with speed.  You can use the mildest counter steering inputs to great effect at slow speeds but racers really need to work to turn a bike that's moving at 150-200mph.

There have really been vast improvments in the understanding of how and why a motorcycles handle the way they do in the last 20 years.  Fork rake, wheel weight, wheel diameter, and so many other things play a part but trail is really one of the strongest factors.  In fact a bicycle or motorcyle stays upright on it's own mostly because of trail, not gyroscopics.  I believe there was an experimental rig built with counter rotating gyros to cancel the gryo force of the wheels, still totally ridable because of trail.  Without cutting and rewelding the frame or making big fork mods it's hard to modify trail.  The easiest thing to do is change tires or suspension heights which may have a smaller effect but still has some.

All that said, there are things to keep in mind.  Physics is often non-intuitve.  This is a theoretical discussion of a single element that may or may not be the cause of a real motor bike that is a complex collection of moving systems.  Sometimes something that makes no sense in theory fixes a problem.  You could probably get to the root of why but it's often not worth figuring out.

Wow!  And you thought it was deep before!

As you said, a few dollars to see what happens.  I just have an ingrained need to know why.  Ignore me at your leisure ;)

Scott
WOW !!!!!! HEAVEY!!!!, I think from now on it's ProfessorScotty. LOL. It is very good indeed to have you involved in this complex conundrum. And yes the Why about it, is what's  Driving me to such extreme and complex platitudes. :D
 Thanks Scott, Dan.
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gashousegorilla

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Reply #52 on: July 09, 2010, 04:29:45 am
OK, Had some positive results tonight. Cut and tac -welded in the 1" cross brace on the swing arm. I tac-welded because were just experimenting for now. Put everything back together and took her for a ride. Some slower speed stuff first for safety. Initial impressions were that the bike felt more solid and slower speed handling seemed unaffected.
 Pulled over to check the welds, and see that everything was in order. Then hopped on the closed course Highway. I got a 10-15 mph increase in stability :o. I found that I could cruise comfortably at 70mph. Not bad Huh?, but anything above that, the bike would start to get squirrely . So I think it's a decent improvement, but there's room for more. Time to try the Rube Goldburgish wheel weight test ;D. then onto a probable tire and or wheel size increase. I got pic's, but again, I can't get them to upload. Come on guy's any idea's.
 Dan.
« Last Edit: July 09, 2010, 04:34:17 am by gashousegorilla »
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Ducati Scotty

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Reply #53 on: July 09, 2010, 07:55:51 am
If you're running any current version of Windows then 'Paint' is a program that's probably already installed.  It's not much but it can shrink the size of files by just making them smaller, no fancy 'save at a lower resolution stuff, just fewer pixels.  Try that and see if you can get a smaller file that you can upload.

And nice job!  From what I've read all around here 70 is the highest comfortable speed well sorted stock bikes go.  And that's chassis stability comfy, engine vibes get grumbly at that speed. 

If this works out you might start getting swingarms mailed to you to improve :)

Scott


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Reply #54 on: July 09, 2010, 08:12:52 am
WOW !!!!!! HEAVEY!!!!, I think from now on it's ProfessorScotty. LOL.

I second the motion  ;)

All in favor say aye  
 ;D



All kidding aside, my sincerest thanks for providing more useful education in that one post than four years of high school science class.
« Last Edit: July 09, 2010, 08:20:25 am by Ice »
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Reply #55 on: July 09, 2010, 01:58:22 pm
I have software that will reduce the pixle size of your image.  Paint gets a bit squirrely if you try to resize it much.  I can do it with no loss of quality.

Feel free to send me the files and I will do it an send them back to you.

-Q
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Ducati Scotty

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Reply #56 on: July 09, 2010, 05:21:20 pm
Now that's community :)


gashousegorilla

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Reply #57 on: July 09, 2010, 06:51:44 pm
I second the motion  ;)

All in favor say aye  
 ;D



All kidding aside, my sincerest thanks for providing more useful education in that one post than four years of high school science class.

AYE!!!!!!!!!
 Thanks boy's but don't send them in just yet, I'm going to take it all back apart tonight and finish off the welds, grind and paint nicey nice, then put some miles on the bike to make sure everything is cool.Were stiffening something up, just want to make sure it does not show up somewere else in the form of a crack, I'll be the Guiney Pig. By the way, I do not believe bronze bushings are gonna work, due to the fact that the face of the plastic bushings ride flush up against the inside of the frame.Plastic to metal. Bronze would grind into the Frame. For lubrication, it's a simple matter of pulling out the pivot bolt and squeezing in some grease, support swing arm though. I will probably still add grease fitting by projects end.
  Scotty, vibs are really not that bad at 70 mph, especially for a single. By comparison I would say it's a little better than a 1200 Sporster.And what they say around here about the motor smoothing out with time, is true, it definitely does.
  For the pic's I have some before shots, gotta take some after shots.will due,then try paint, as the Professor suggests,  ;D. If not I'll email them to you Golden for your magic touch.
 OK? Now let me get out of here and get back to work. I'll get wit yooz  Guys latta. Sorry, "You Gentlemen Later", That was my Jersey slipping out.
Dan.  
« Last Edit: July 09, 2010, 06:56:04 pm by gashousegorilla »
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gashousegorilla

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Reply #58 on: July 10, 2010, 04:30:26 am
Some before pics. Cool, paint worked! Below you will see the comparison of the cb350 swing arm on the left and C-5 swing arm on the right along with pics of measurements of the C-5 swing arm.
« Last Edit: July 10, 2010, 04:36:40 am by gashousegorilla »
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gashousegorilla

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Reply #59 on: July 10, 2010, 04:44:25 am
Here's some more. What the............. how did that last one get in there?  Oh well you got a preview of my next project. ::)
« Last Edit: July 10, 2010, 04:47:50 am by gashousegorilla »
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Reply #60 on: July 11, 2010, 01:02:51 am
Not that we are not interested in what you are doing, and want you to document every detail, leaving no stone unturned in your quest for improvements, ...but...Look at which picture has had the most hits!      ;D
Any other Enfields in New England?


gashousegorilla

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Reply #61 on: July 11, 2010, 04:28:27 am
Not that we are not interested in what you are doing, and want you to document every detail, leaving no stone unturned in your quest for improvements, ...but...Look at which picture has had the most hits!      ;D
Yea right? Geeeez,swing arm schming arm. Who cares. All you guys think about is sausages and side cars? :D  
 Couple more coats of paint, and I'll post some pics of the modified swing arm. Or maybe not, maybe I'll  just post a pic of some tricked out Trike with a deep fryer on the back. Geez  La- Weez!
« Last Edit: July 11, 2010, 04:38:22 am by gashousegorilla »
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gashousegorilla

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Reply #62 on: July 12, 2010, 05:28:45 am
OK boy's , here you go, strong and beefy modified C-5 swing arm. 1" pipe welded in. With 1/4" flat stock fitted and welded in center of pipe for good measure. Painted up and ready to go. Pivot bolt spacer packed with Triple guard super blue Evinrude grease. Put it all back together tonight, and took her for a quick test.All in order so far, same results as last test with pipe tacked in. 10-15 mph improvement in stability. Stable cruising up to 70mph, after that front end starts to feel light and squirrely. Time to move on to the front end. 19" wheel , perhaps. maybe a Damper, maybe even wider bars?
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Reply #63 on: July 12, 2010, 01:34:41 pm
If I remember correctly, the swing-arms from the Enfield twins like the Interceptor had braces like that in them.

It looks like you did a nice job.
Love the Incredible Hulk holding the swing-arm!

For what it's worth, I'm getting some spidey sense tingling that is making me think that you are getting drag-induced lift of the front suspension, making the bike light in the front at speed.
Try leaning forward a bit, and see if you can reduce the "parachute effect" of your body against the wind, and see if that helps the stability some. Maybe you need lower bars.
Home of the Fireball 535 !


gashousegorilla

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Reply #64 on: July 12, 2010, 03:32:11 pm
If I remember correctly, the swing-arms from the Enfield twins like the Interceptor had braces like that in them.

It looks like you did a nice job.
Love the Incredible Hulk holding the swing-arm!

For what it's worth, I'm getting some spidey sense tingling that is making me think that you are getting drag-induced lift of the front suspension, making the bike light in the front at speed.
Try leaning forward a bit, and see if you can reduce the "parachute effect" of your body against the wind, and see if that helps the stability some. Maybe you need lower bars.
Thanks Ace.  Very intesting about the twins, I was not aware of that, but it would make sence. Also a very good thought on the parahute effect. Us ton up boys are not use to such peculiar phenomina , being all hunched over on our clubmans,like you see below :D Scott any thoughts. ???  Makes sence to me.at least a contributing factor. I read a good peice on wiki about bike stability, it said the most critical part of the bike's stability is rider input.
« Last Edit: July 12, 2010, 06:29:23 pm by gashousegorilla »
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Ducati Scotty

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Reply #65 on: July 12, 2010, 04:19:44 pm
With that in mind, wider bars would only amplify rider input.  Stick with the stock bars and practice good form: grab the tank with your knees and hold a very light grip on the bars.

Still, I think that both drag and short trail are probably also big contributors to current instability.  Leaning forward is an easy and cheap experiment.  Also, make sure the tank is full for your next run.

Scott


gashousegorilla

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Reply #66 on: July 12, 2010, 04:43:56 pm
How bout the effects  of a cinder block tied to the down tube? And it's aerodynamic effects ?  :D
« Last Edit: July 12, 2010, 04:46:23 pm by gashousegorilla »
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Ducati Scotty

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Reply #67 on: July 12, 2010, 05:41:41 pm
Oh, and the fact that there was no gusseting or reinforcement to start with seems weird.  I think I'd be apt to do this mod just for peace of mind.

Scott


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Reply #68 on: July 12, 2010, 07:40:01 pm
 Seriously, I would like to thank ALL of you guys for your positive input with this issue. I think WE produced a pretty good  improvement in the high speed stability of my C-5.Theres still room to go, but it worked so far in my case.
  In particular I would like to thank chinoy,who recognized early on the weakness in the swing arm design, when many of us were on the fence or looking else where. Chinoy knows his Stuff, He's a cafe builder/mechanic, and knows his way around a BikeAnd must agree that a bike should be stable to it's maximum claimed top speed. Or a little further. We westerner's must remember,that for us by and large, motorcycling is a hobby or pass time. We like to think of ourselves as "Biker's" , "Rocker's, "Ton-up Boys", or whatever.Some of us are, some are not. Whatever your involvement it's cool. For the people who live in the East, Far East, and other parts of our world, motorcycles are as mundane as our SUV's and Minivans with the magnetic soccer Ball on the back.In otherwords they Live on their bikes, and could teach us a thing or two.The sharing of knowledge is a gift and should be treated as such.
 Also in particular DucatiScotty, a.k.a The professor ;D Who I think is a Closet Engineer, but ain't Say'in, and Ace-Cafe, who with a name like that must be a Rocker, for there useful tech input.
 Thanks Boy's, Dan.
« Last Edit: July 12, 2010, 08:00:06 pm by gashousegorilla »
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r80rt

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Reply #69 on: July 12, 2010, 08:29:46 pm
I still don't understand it, my C5 handles very well. I think the size of the rider has something to do with it, I'm 5'5" and weigh 175lbs with short legs. I sit a bit farther forward than most folks and I'm not tall enough to catch a lot of wind, it's feels a bit light over 70 but I almost never run over 60-65mph, it's very stable on the twisty roads around here and a ton of fun to ride. Or is this just a goofy theory?
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qgolden

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Reply #70 on: July 12, 2010, 08:37:48 pm
I think pilot weight has a lot to do with it.  I agree with r80rt, mine seems ok, but I do not exceed 65 to 70 either, prefer a 45 -50 mph back road to the highway. the Enfield handles those roads far better than the Road King.   I am 5"11 at 195 dressed in riding gear.

I have never been a high speed rider so I really would not be able to recognize the symptoms that gashousegorilla experienced. But I am glad he broke from the pack and sorted it out for the rest of us. That is how innovation works.

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Reply #71 on: July 12, 2010, 09:06:05 pm
The aero drag on the rider, or drag on anything high up on the bike, causes a rearward pressure that is translated into lift at the front end. This is because that drag force becomes a torque moment around the rear axle, and the vector is up and back in direction. It's like it's trying to make you do a wheelie.
The faster the speed, the higher the aero drag, and the more the front end lifts.
As the front end lifts, weight distribution is transferred off the front wheel to the rear wheel, resulting in front end instability.

Reduce aero drag, go slower, or lower the location of the aero drag, and you'll get less lift.
Aero drag increases as a cube relationship to speed, so the aero drag increases alot faster than your road speed does.

The rider is perhaps the biggest aero drag component on the bike. Lowering and streamlining the rider can have a profound effect on many aspects of the bike's performance, including acceleration and top speed, as well as load on the engine at any speed.
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Ducati Scotty

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Reply #72 on: July 12, 2010, 09:46:22 pm
You're welcome Gorilla.  Strictly speaking, I was failing out of engineering school when I switched to computer science as all good failing engineering students do :)

Seriously, not being an RE owner yet I hadn't taken a close look at the swingarm.  I think my 1977 Hnoda XR75 dirt bike had more swingarm bracing than the stocker you showed.  I seriously would pull that off and get something welded in at the first convenient time.

Just curious, why the piece of flat stock welded in the middle of the brace?  Better torsional rigidity?  Just easier to cut and shape the fish mouths on the ends of the new piece?

Scott


gashousegorilla

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Reply #73 on: July 12, 2010, 10:28:39 pm
Well I hope your old professors are reading this thread Scotty ;) And yes to both. Just easier to fit and get correct, Things love to move around when you weld. Because the stock swing arm springs open so much, it take;s some tweaking to get the dimensions right. Still be able to get the wheel on OK, but not too much stress on the bearings,etc.I might do it different next time with a jig, but hay this is the first one.
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Ducati Scotty

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Reply #74 on: July 12, 2010, 11:19:35 pm
Yeah, would be good to measure the rear wheel width, maybe add 1/8" -1/4" or so, and jig it that far open.  Still, things move when they get hot unless you want work like a body panel welder:  weld 1/8" of bead, let cool completely, repeat until done.  Too much time.

Scott


gashousegorilla

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Reply #75 on: July 13, 2010, 01:21:57 am
I think pilot weight has a lot to do with it.  I agree with r80rt, mine seems ok, but I do not exceed 65 to 70 either, prefer a 45 -50 mph back road to the highway. the Enfield handles those roads far better than the Road King.   I am 5"11 at 195 dressed in riding gear.

I have never been a high speed rider so I really would not be able to recognize the symptoms that gashousegorilla experienced. But I am glad he broke from the pack and sorted it out for the rest of us. That is how innovation works.

-Quinn

 Thanks for the kind words ggolden.
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gashousegorilla

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Reply #76 on: July 13, 2010, 03:30:53 am
I still don't understand it, my C5 handles very well. I think the size of the rider has something to do with it, I'm 5'5" and weigh 175lbs with short legs. I sit a bit farther forward than most folks and I'm not tall enough to catch a lot of wind, it's feels a bit light over 70 but I almost never run over 60-65mph, it's very stable on the twisty roads around here and a ton of fun to ride. Or is this just a goofy theory?
Not goofy at all. Don't let my user name fool you, I'm not a Gorilla in stature by any stretch. Like you, if I may, I would say I'm below average in size. 5'8 or 5'9, bout 175lbs. And I'll go a little further and say the C-5 handles exquisitely on the county roads. Now I'm 3-4 inches taller then you, and there is about a 10 mph difference in our bikes stability, if all things being the same. Before this swing arm mod, other then a pedestrian slicer, my bike is bone stock. Your bit light at 70 mph, Things start getting getting scary for me. See my point? It should not Be.
 Someone said earlier in this thread, it has to do with expectations. Excellent point.And I expect a bike with a very modest claim of a maximum speed of about 82 mph to be stable for the average rider at that speed. For me , I live in a suburban setting, closer to city's then the country. And from time to time I have to jump on an interstate to get to those country roads. I simply would like to have a stable enough bike to feel confident about cracking open the throttle and passing that double hitched tractor trailer.I think my expectations are pretty reasonable,no?
 I did not purchase this bike to go tear a!!ing around, I build Cafe racer's for that. I bought it because it is an awesomely cool old school bike, that I did not have to do a thing to,or so I thought .I have a day job. I spend most of my free time working on,or building bikes for other people,so you can get my frustration.I don't mean to whine, I'll get it figured out. sorry for the rant.

Thanks, Dan
« Last Edit: July 13, 2010, 03:41:30 pm by gashousegorilla »
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Reply #77 on: July 19, 2010, 03:47:36 pm
I am late to this discussion but i hope this link helps. The author discusses a few options to brace swing arms which look like useful alternatives to others who want to give this a shot.
http://victorylibrary.com/brit/chassis-2a.htm

That swing arm looks like a poor cousin of a torsion-beam axle and though i am no engineer, i am surprised (and not pleasantly either) to see such a design. As Chinoy said, there are motorcycles in India running what would to you folks be lawn-mower engines with better designed swing arms.

Dan sir, great work with the brace! I am sure a lot of people will follow your path. I would humbly suggest flat sheets on top and bottom to form a box shape to reduce the possible deflection further. You could cut a circular hole in the middle of these sheets to reduce weight while keeping the stiffness. The only fly in the ointment i see is if something attaches to the small blob(??) between the swing arm pivot and your brace.

I had one question. When the swing arm goes back on the engine, how would one ensure that the rear wheel is along the same vertical axis as the front wheel? I have seen C5s with rear wheels canted over to the left (as seen from the rear) when in motion.


SSR

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Reply #78 on: July 19, 2010, 04:09:04 pm
Going by the manual when putting the swing arm back in, its should be aligned with two ruler like metal strips bolted on the top and bottom shock absorber.

The reason you see the bad angle at the rear is mostly due to the chain adjuster splines not the same no on either side.


Ducati Scotty

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Reply #79 on: July 19, 2010, 05:07:54 pm
From that article:
"The pivot shaft needle bearing is one of those “looks like a good idea” that doesn’t work. The original bushing is generally either self-lubricating (“Oilite”) or has a gease fitting nipple, but has far higher load capacity than a needle, and doesn’t require a specific minimum surface hardness (or finish) to run on.
    There is also no gain to be had in any event - the swing-arm pivot does not rotate in the bearings but only oscillates a few degrees, so the difference in friction is too small to matter. "

Good to know.  Probably best to do what Gorilla did or similar or maybe more so by boxing it in as you mentioned and radiusing the rear to match the tire.  Whatever you choose, it seems the stocker is, um, shall we say 'lacking'.

Scott


gashousegorilla

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Reply #80 on: July 20, 2010, 01:52:16 am
I am late to this discussion but i hope this link helps. The author discusses a few options to brace swing arms which look like useful alternatives to others who want to give this a shot.
http://victorylibrary.com/brit/chassis-2a.htm

That swing arm looks like a poor cousin of a torsion-beam axle and though i am no engineer, i am surprised (and not pleasantly either) to see such a design. As Chinoy said, there are motorcycles in India running what would to you folks be lawn-mower engines with better designed swing arms.

Dan sir, great work with the brace! I am sure a lot of people will follow your path. I would humbly suggest flat sheets on top and bottom to form a box shape to reduce the possible deflection further. You could cut a circular hole in the middle of these sheets to reduce weight while keeping the stiffness. The only fly in the ointment i see is if something attaches to the small blob(??) between the swing arm pivot and your brace.

I had one question. When the swing arm goes back on the engine, how would one ensure that the rear wheel is along the same vertical axis as the front wheel? I have seen C5s with rear wheels canted over to the left (as seen from the rear) when in motion.
Thanks for the kind words and that very useful link ajithk. I wish I had it before I started this modification. But all the same I think I would have done the modification the same way. I agree that a boxed, arch shape design would be stiffer, using 16 ga steel or a solid 10ga steel arched plate welded in between the side tubes. But as stated earlier in the thread I believe in going a little conservatively the first time around.
 The arched shape designs would improve the stiffness by a factor of two, the simple 1" cross brace improves it by a factor of about 1.40. Point is this is an unknown modification at this point, or at least as far as I know. We don't know what if any impact it will have on the frame of the bike.Particularly the side gussets where the pivot bolt mounts the swing arm to the frame.
  The arched shape designs we see on other bike's are usually , but not always, supported in the center of the span by another frame member, like a stamped  steel post if you will.
  The blob as you so kindly put it ::), again was explained earlier in this thread. I don't see it as an issue unless you were to ride on mirrored roads ;). Again this being the first, and in absence of a Jig, it was a accurate way to adjust the dimension's of the swing arm for ease of installation of wheel, the ability to adjust the chain/wheel alignment, without too much stress on the wheel bearings. The 1" brace was welded in, sliced, adjusted, and welded back together with a 1/4" piece of flat stock.
 Or maybe you were reffering to my fat little friend? :D
 Thanks ,Dan.
« Last Edit: July 20, 2010, 01:56:35 am by gashousegorilla »
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gashousegorilla

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Reply #81 on: July 20, 2010, 02:26:27 am
Going by the manual when putting the swing arm back in, its should be aligned with two ruler like metal strips bolted on the top and bottom shock absorber.

The reason you see the bad angle at the rear is mostly due to the chain adjuster splines not the same no on either side.
Or you could just use the shock absorber. There is nothing to align really. The position of the swing arm in the frame is determined by pivot bolt mounting area's. I suspect it's stated that way in the manual because thats how they do it at the factory. It's cheaper to use a couple of pieces of drilled out flat stock, than to give the guy at his assembly station  a pair of pricey shocks. They can also sell the dealer this handy specialty tool. :D
In my work on the swing arm, really saw no need for it.
 I also forgot to mention earlier on in the thread, that the reason, at least in part, for your axle/ chain adjusters not being on the same notch, is because the swing arm side tubes are not perfectly symmetrical. Remember when I said that when you loosen the axle nut, the swing arm springs open? Well, with the stock swing arm having so much flex, when you tighten everything up, the side tubes do not pull in at the same rate. Leaving the rear wheel misaligned in the swing arm. It's really not an issue per say, as long as you have a slotted section in the swing arm, where the axle passes, to adjust for irregularity's. All bikes have them, for the most part. But with the week swing arm design on the C-5, you just have to use more of that slot to compensate. Another words, if your axle adjusters are not on the same notch, it's probably cool , as long as your alignment is OK.
 Dan.
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Ducati Scotty

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Reply #82 on: July 20, 2010, 04:55:15 am
Yup, align the wheel to the bike frame or the other wheel.  Little marks on the swingarm are always inaccurate.  I usually just lay a ruler or other straight edge along the rear sprocket, it should fall in line with the chain.  Unless the engine is really crooked in the frame it's certainly close enough and is really quick.

Gorilla, did you leave the rear of the swingarm open a little bigger than the width of the wheel?  How much?  Just thinking in advance.  I'll have to get this done since I don't weld.  I figured I'd put a bolt across the rear to hold it at a set width while the piece gets welded.  Keeps things in line.

Scott


gashousegorilla

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Reply #83 on: July 20, 2010, 06:36:40 am
Good idea Scott. Threaded rod, 4 nuts, 4 washers. Lock  everything in place. At the point where I sliced the 1" brace, in the center, it was about 1/8". What I did was to then wedge the sliced brace with a steel chisel,and then check for correct fitment on the    fully assembled rear axle/wheel , open up Slice to fit 1/4 inch stock, then weld it up. What the spread is at the rear where the axle slot is, I'll have to loosen up the axle nut and measure it for you, let me know when your ready. But to be honest Scott, I think doing the wedge technique is more accurate and more forgiving.And not that much more work. I would bet that there are variations from swing arm to swing arm. Remember, those two side tubes are over 18" and  what are the chances of getting perfectly straight sections from bike to bike? Especially after factory welding. Those side tubes are just butted against the pivot tube, at an angle and welded in place. I don't know how good their jigs are. so what worked for me, may not for you. What happens to the Brace, when you weld it, is that it shrinks over it's length from it turning from a solid to a liquid. difficult to predict. HOT LAVA!!! Be careful because the side tubes flare out from each other, so the axle slots are going to measure narrower at the front then at the rear. It is probably best just to fit it.
 Your welder should be able to do it, no prob. Just bring him the wheel assembly and show him how it goes together.
 Dan.
« Last Edit: July 20, 2010, 07:02:03 am by gashousegorilla »
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ajithk

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Reply #84 on: July 20, 2010, 01:13:01 pm
 The blob as you so kindly put it ::), again was explained earlier in this thread. I don't see it as an issue unless you were to ride on mirrored roads ;).
I did not mean the brace itself. Between the attach point of the brace on one of the arms of the swing arm, and the bar which also forms the pivot, there seems to be an attach point (The blob). I suspect the brake stabilizer rod attaches there?

   Or maybe you were reffering to my fat little friend? :D
 Thanks ,Dan.
;D hehehe


Ducati Scotty

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Reply #85 on: July 20, 2010, 01:52:23 pm
Dan, I suspect their jigs and final products all have a little play.  I was just wondering how much.  I have a friend of a friend who's a welder and a couple of frame shops in town, I'm sure someone can do it.

Also, yeah, just butted up and welded?  While it's in the welder's hands I'd have him put some gussets on the joints at the pivot tube.  Of course then I'd have to get the bushings out first....

Scott


gashousegorilla

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Reply #86 on: July 20, 2010, 04:29:25 pm
I did not mean the brace itself. Between the attach point of the brace on one of the arms of the swing arm, and the bar which also forms the pivot, there seems to be an attach point (The blob). I suspect the brake stabilizer rod attaches there?
 ;D hehehe
Oh,OK,sorry ::). on the right hand side of the swing arm ,near the junction of the side tube and pivot tube, is a welded in threaded  bung. This is an attachment point for the chain guard.
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gashousegorilla

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Reply #87 on: July 21, 2010, 01:06:45 am
Dan, I suspect their jigs and final products all have a little play.  I was just wondering how much.  I have a friend of a friend who's a welder and a couple of frame shops in town, I'm sure someone can do it.

Also, yeah, just butted up and welded?  While it's in the welder's hands I'd have him put some gussets on the joints at the pivot tube.  Of course then I'd have to get the bushings out first....

Scott
Yup, Butted up. They were probably fish mouthed though.Welds did not look bad, I don't think I would worry about them breaking. Bushings are easy, to remove without destroying, with a LITTLE heat and a wooden dowel, just carefully tap around the inside edges. If you install gusset's , just be sure to leave clearance for the chain guard mount on the right side.Have him grind everything nice, get a can of self etching primer, a can of color, sand paper and good to go. I used chip resistant Duplicolor caliper paint. My bike is black, so easy to match. If you get the red or teal, thing get more complicated. Maybe you can find a Duplicolor stock can to match? Sold at your local auto chain store. A black swing arm may work to? I don't know how difficult it would be to get a can of touch up from your dealer? If you have to go the route of getting a color match from a auto paint supplier, your talking about $75-$100 bucks for a decent single stage urethane/activator.
 Any advice you need, let me know, no prob. Maybe we could hook up in say, Iowa, half way, right? :D
 Good luck, Dan.
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Ducati Scotty

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Reply #88 on: July 21, 2010, 03:06:46 am
I'm not that picky, it's buried under the bike.  The closest DupliColor rattle can from a Chevy or whatever will do.  I painted my own Dark Monster fender and it came out good enough that no one ever noticed.  Talk to a painter about trying to match Ducati Dark black one day, it's no picnic.

Can we change the name of this thread to 'Gorilla Swingarm Mod avec le 19"wheel'?

And how does it ride with the 19" tire and 18" wheel? :P

Scott


gashousegorilla

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Reply #89 on: July 21, 2010, 03:32:30 am

Can we change the name of this thread to 'Gorilla Swingarm Mod avec le 19"wheel'?

And how does it ride with the 19" tire and 18" wheel? :P

Scott
Yes ,I think we should. It would make things much easier.

But what do dem French words mean ???, You didn't curse at me, did Ya? :D   
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