[Chilliman]

Hi all,

being new to the C5, I look and try to find out what I can about every aspect of the C5.
I come across posts about "violent" wobbles of the C5 above 100kmh.

Any takers on this subject?

[ace.cafe]

In the early C5, it was prevalent, but not everyone experienced it. Some cures were found with sorting out anomalies in the rear subframe and rear suspension.
Gashousegorilla did a lot of experiments with his, and improved things on his bike. Some others followed suit.

Subsequently,  the factory recognized the matter, and then the C5 started coming with the 19" front wheel.

It has not been a problem since then.

[Chilliman]

Thanks for that

[dickim]

Had mine to an indicated 105/110kmh (o.k so we all know that is not accurate) but NO issues on my 2014 C5 - in fact this weekend took a Guzzi Cali 3 for a run that I have just bought as "Donor" for a trike (Morgan Style) and it made me realise how much I love my "Old School" C5

[malky]

Hi all,

being new to the C5, I look and try to find out what I can about every aspect of the C5.
I come across posts about "violent" wobbles of the C5 above 100kmh.

Any takers on this subject?

Putting on over size tyres can have weird effects also. Especially on the rear, with a passenger aboard.

[gashousegorilla]

Hi all,

being new to the C5, I look and try to find out what I can about every aspect of the C5.
I come across posts about "violent" wobbles of the C5 above 100kmh.

Any takers on this subject?

   Stock C-5, with a 18" or 19 " front wheel chilli ?

   Anyway's the basics would be...

  Tire pressure !   They are not wrong in that book when they say 18 psi in the front. I found 18-20 front and 26-28 in the back is about ideal.     You CAN run higher pressures ?..... but when at speed , say above 60- 70 mph your stability will start coming apart.  You may find that bike staring to weave a bit on you.  I found that pressure to work well on both the stock low profile and very stiff side wall Avon road riders , and the K70's.  Either tire at those higher speeds with the pressure too high will send it into weave.   

   Steering stem bearing adjustment... I like it on the tighter side.  Swing arm torqued to spec. Alignment. AND.. make sure your tail section IS supported at the front of the rear fender , under he seat.  You should see a rubber bush under there, where the rear fender slides into.   If not, that pretty heavy tail section can start swinging in breeze a bit back there at speed, upsetting the frame.

 

[Blairio]

   Stock C-5, with a 18" or 19 " front wheel chilli ?

   Anyway's the basics would be...
 
   Steering stem bearing adjustment... I like it on the tighter side.   

I wonder whether there is a case for trying a steering damper, rather than nipping the steering column bearings up? Mind you, nipping those bearings up is a simpler solution.....

[gashousegorilla]

  You can try it Blair ?  I did way back when.  In my case I found a steering damper didn't do much of a damn thing if the rest of the chassis wasn't set up right.  BUT.. when it is set up right, I do believe  a damper could help prevent a violent tank slapper .   For the most part though ,we don't ride theses bike in such a fashion where that would happen.  The problems that I had or some of us had back then , were  not really head shake or tank slappers ....  It was sudden loss of, and sometimes violent loss of stability  over speeds of 50-60 mph.  The whole bike would become unhinged and go into a weave....

  There isn't all THAT much adjustment I have found with those stem bearings.   You could tighten the hell out of the bearings and still move the front end side to side..... not that I'm recommending that !  But point is,  you can not LOCK the front end in place  like you could with other bikes.   It doesn't do all that much on these bikes.... Unless they are TOO loose.    Just snugged down and locked in with no play.   

[Chilliman]

DANG !!!
I've got an 18inch front wheel with an almost new Avon on it.
The roads around the Northern Territory have hundreds of triple and quadruple trailer road trains on most roads.
Because of the weight they carry most roads have a slightly higher centre of the lane to the outer section where wheels run but they are not very even.
So when you ride the "train tracking" effect is noticeable.
I will take on board the 19 inch front wheel and go grab one I think.
Thanks for all the input.

[Jako]

Along with the 19" front wheel they also did away with the leading axel forks.

[gashousegorilla]

  Yeah Chilli..... I would go with the 19 " front  even with the leading front axle like on our older bikes.    That 120 x 18 rear tire you put on there is good .   Not only is it wider then the 110 x 18 tire that WAS on there... but it is also going to be taller.  It will be very close to the 90/90/19 that you are likely to put on that front wheel.    The bike will sit nice and level.   You MAY want to get 1/2" LONGER then stock, rear shocks as well.  Set your sag to about 3/4-1".   The slightly taller ass end will shift your weight more forward on the bike... this will stabilize things and make the two separate frames of the bike... the front end , and everything on the rider side of the steering stem more stiff.   Lower Handlebars help here too.   The bike will handle great in the corners and twisties  AND in a straight like Blasting down the highway.   And use those lower tire pressures on that Enfield.   I don't care what any body else tells you.  I thought it myself and have been through it.  8 years of beating on this bike tells me so. 

   Drain that sorry excuse for fork oil out of those front legs.   And put in 265 Ml of real fork oil... 15 or 20 weight.   Use 10 or lower weight if you want it to ride like a sponge .    

 You wanna get real crazy ?  ... stiffen the swing arm with a cross brace, an arch brace or a trellis brace .  Loose that massive rear end with it's heavy ass fender and stays that tie into the main frame ?   And OMG !....  will you have a nice handling bike ! 


 You CAN have the bike running nice and stable in it's stock form now, with the stock motor. Right up to the maximum speed that a stock motor can put out... without any money, but just a little time and chassis checking.  But, your doing that motor work like I did ?    Your gonna want it stable right up to that ton and beyond like you are shooting for.   

   When you have that motor out of the bike and it's all taken apart.... Check the frame tubing for anything that is not square.  Check you all your motor mounts and corresponding holes in the motor.  Make sure that the motor sits in there snugly and squarely  with out any stress.   You shouldn't have to force anything in.  Modify those motor mounts if you need to.  That is where a LOT of the problems with vibs and cracked frames on these bike come from I believe.   Get it right and your bike will be SO much better if you are having a problem with it....  What blue loctite ?!   

[Blairio]

  You can try it Blair ?  I did way back when.  In my case I found a steering damper didn't do much of a damn thing if the rest of the chassis wasn't set up right.  BUT.. when it is set up right, I do believe  a damper could help prevent a violent tank slapper .   For the most part though ,we don't ride theses bike in such a fashion where that would happen.  The problems that I had or some of us had back then , were  not really head shake or tank slappers ....  It was sudden loss of, and sometimes violent loss of stability  over speeds of 50-60 mph.  The whole bike would become unhinged and go into a weave....

  There isn't all THAT much adjustment I have found with those stem bearings.   You could tighten the hell out of the bearings and still move the front end side to side..... not that I'm recommending that !  But point is,  you can not LOCK the front end in place  like you could with other bikes.   It doesn't do all that much on these bikes.... Unless they are TOO loose.    Just snugged down and locked in with no play.

I get you. I don't have that great a memory, but equally I don't remember anyone experiencing that kind of front end wobble on a G5 / Electra (like mine).  Are the frames that different between G5s and Classics? Or is it all in the front wheel size and whether the axle is offset against the fork?

[Chilliman]

  Yeah Chilli..... I would go with the 19 " front  even with the leading front axle like on our older bikes.    That 120 x 18 rear tire you put on there is good .   Not only is it wider then the 110 x 18 tire that WAS on there... but it is also going to be taller.  It will be very close to the 90/90/19 that you are likely to put on that front wheel.    The bike will sit nice and level.   You MAY want to get 1/2" LONGER then stock, rear shocks as well.  Set your sag to about 3/4-1".   The slightly taller ass end will shift your weight more forward on the bike... this will stabilize things and make the two separate frames of the bike... the front end , and everything on the rider side of the steering stem more stiff.   Lower Handlebars help here too.   The bike will handle great in the corners and twisties  AND in a straight like Blasting down the highway.   And use those lower tire pressures on that Enfield.   I don't care what any body else tells you.  I thought it myself and have been through it.  8 years of beating on this bike tells me so. 

   Drain that sorry excuse for fork oil out of those front legs.   And put in 265 Ml of real fork oil... 15 or 20 weight.   Use 10 or lower weight if you want it to ride like a sponge .    

 You wanna get real crazy ?  ... stiffen the swing arm with a cross brace, an arch brace or a trellis brace .  Loose that massive rear end with it's heavy ass fender and stays that tie into the main frame ?   And OMG !....  will you have a nice handling bike ! 


 You CAN have the bike running nice and stable in it's stock form now, with the stock motor. Right up to the maximum speed that a stock motor can put out... without any money, but just a little time and chassis checking.  But, your doing that motor work like I did ?    Your gonna want it stable right up to that ton and beyond like you are shooting for.   

   When you have that motor out of the bike and it's all taken apart.... Check the frame tubing for anything that is not square.  Check you all your motor mounts and corresponding holes in the motor.  Make sure that the motor sits in there snugly and squarely  with out any stress.   You shouldn't have to force anything in.  Modify those motor mounts if you need to.  That is where a LOT of the problems with vibs and cracked frames on these bike come from I believe.   Get it right and your bike will be SO much better if you are having a problem with it....  What blue loctite ?!   

Maaaaaaate !
Sounds like we are on a similar wavelength.
Over the years I always did the motor work and asked blokes who were frame experts about what to do with any power that happened to be floating around.
I pretty much go everywhere two up with my good wife.
She is tiny.
I guess it looks like Jabba the Hut with Tinkerbell on the back. Not quite but I'm sure you get the picture.
Bit scary at first. She grew up in Saigon very used to scooters doing 60kmh. (she is 48)
But the first time we went out on Roy, (our C5 Bullet) we nearly ploughed into a few fences because she had no concept of laying over in corners at speed.
I felt like gluing velcro to my back and the front of her jacket so she was glued there but now she loves the corners.
A woman that always "gets it", as in understands the concepts.
Okay now. I reckon I'm gunna have to get that 19" front wheel.
Cheers all.

[Kevin Mahoney]

Wobble was only a problem in 2009 and maybe 2010 models. They took 3 degrees out of the rake. You can tell by looking at the fork tubes. If they go straight down they are the ones that can cause trouble. The new fork places the axle ahead of the line of the fork where it belongs. It is only a C5 issue

[gashousegorilla]

I get you. I don't have that great a memory, but equally I don't remember anyone experiencing that kind of front end wobble on a G5 / Electra (like mine).  Are the frames that different between G5s and Classics? Or is it all in the front wheel size and whether the axle is offset against the fork?

  Yeah, me neither.  The G-5's are MUCH more stable then those early C-5's.... Oh gawd, it's like night and day.    I have found that the G-5's almost  DON'T want o turn with those stock Skid masters on there. LOL !  Better tires help immensely with that I have found.  REally a great riding bike all around  with better tires on there.  I will say even at that though .... they can and WILL act in a similar fashion at high speed to the C-5 if the tires pressures are too high.  But nowhere near AS bad.   The front end can start feeling a bit toooo lite. But quite easily fixed with the correct pressure.

   I currently have both a 2009  G-5 and C-5 in my garage. The over all "main" frames are pretty much the same. Some minor differences in mounting tabs locations and such here or there. Same front leading off- set front axle.  The biggest differences I see are ...  The G has 19"  wheel's front AND back, as opposed to a early stock C, which had 18's front and rear.  The laced 19" on the rear of the G makes for a much more comfortable ride I think.   The tail sections between the two bikes are very different.  Nothing that is not needed on the G.... nice and secured and compact  and lite.  Where the  C has  big and heavy and unneeded and not very well secured steel bridge like structures back there .     Under that seat, the G ties in the rear of the frame with a loop.... which is very good and makes that frame much more stiff.  THEN they attach the fender and etc. to it.   So it is a good strong base to start with. The C has no such strong arched loop  back there tying the left and right sides of the frame together. They "TRY" to do it through the attached fender and very long fender stays.     Looks aside... I think the G was a much better bike right out of the box.