[gashousegorilla]

Hmmmmm - That's certainly interesting ...... I wish I still had my 19'-wheel test mule here to check that out ...... Is the oscillation set off by wind buffeting from the side? What stops it? Strong-arming the bars? Slowing down? Our "pro rider" here (really - he raced professionally for a few years ...) hasn't mentioned one hiccup with an 18" wheel bike - only acknowledging that you COULD induce an oscillation at high speeds - but that it was a "non" - neither increasing nor decreasing in frequency until you "strong-armed" it a bit and made it stop ...... I've never encountered it yet ........ Interesting, indeed ......

Yea bob, a side to side wind could set it off, along with just about any thing else.Strong arming really does not seem to help, that's why I tried longer bars. Also what does not seem to help or have little impact is different riding positions, leaning back, tucking in,tire pressure adjustments, suspension adjustments, steering play is good, no ruff spots, no play yet not too stiff.etc. etc etc. The only thing that brings her back under control after oscillation starts,is to get back under 60mph.Although I am not a modern sportsbike guy, it seems to be having the same negative handling quality's of the short rake sportbikes, but at lower speed.
Will get it figured, I'm still positive
Dan.

[Ice]

Those wheels do look good on her.

[gashousegorilla]

Though I have already considered a stabilizer myself (and I don't even own an RE yet) it's never good to use them to 'cover up' a problem. 

Another thought, maybe look into a higher profile rear tire.  I was looking up the M26 the other day and they are available in a few sizes.  Maybe if you get the back end just a little higher you can  get that nice balance back.

Another thought, get the front tire dynamically balanced at a shop with a machine.  Couldn't hurt and shouldn't cost too much.

Oh, and check to make sure the steering head bearings are set properly.  Just covering all the bases.

All that failing, maybe a stabilizer is the way to go.  They tend to cancel out those little nudges to the bars that set off the wobble cycle.

Bravo for your persistence and I still intend on 'Gorilla-ing' my swingarm.

Scott

Yea Scotty, wider profile would probably help a little, but it's not going to get me over the hump,if you will. The little fixes just ain't doi'n it.Tire was balanced on a machine,at shop I use for mounting tires. For 20 bucks,it don't pay for me buy a machine. There good though, Drag race old BSA's,hold some record I think. 140 plus mph, on an old 68".
After the test last night,I pulled the wheel and checked it for trueness and balance on my stand,all OK.
Persistent,me?I'm a nut But seriously,that's why we work on bikes, or cars ,or machinery. Were trouble shooter's, and enjoy it.
I am looking foward to the new and improved "DUC BRACE".
Dan.
 

[Ducati Scotty]

Funny, hadn't thought of it but an old school fork brace might help.  They used to have them for many bikes.  It's a big aluminum clamp that grabs both lower fork tubes at their tops and rides right over the tire/fender.  The idea is to make the fork siffer and keep if from twisting.  They're no longer needed with today's sport bike that have large diameter upside down forks that are super stiff.  I think they need to be tailored for the bike so you have clamps of the right diameter to match the fork legs and the righ disance between them.  I think I've also see a few cheap models made of stamped steel that bolt to the fender mounting bolts at the top of the fork lowers.

Which you don't have.  Because you got the C5 instead of the G5.  Foke leg lower swap project anyone?

Scott

[qgolden]

Good thought, I have seen them machined in a clamp arrangement as well.  Two halves machined in such a way that they could be opened up and attached in front and in back of the fork above the fender.  The two halves are then held together front to rear by Cap Screws.   It would fit the Enfield and be cheap to manufacture.

in the meanwhile you could do some testing with a mock up like this to see if it helps.

[qgolden]

Here is a retro-fit-able one that looks a little more professional. 

[Ducati Scotty]

q, that first one is ingenious but ugly   Strictly speaking, you need something big so it's rigid.  That small center section would ned to be much wider and aluminum is better, much more rigid than steel for it's weight.

The second one is nice.  Has the look of  a JC Whitney part to me.  Not that that's a bad thing.

Scott

[qgolden]

Yup ugly is as ugly does!     You could make the center section a lot wider by drilling holes and mounting it on top of the clamps instead of in between them.  You could even put a center section on top and one on bottom and bolt them through the muffler clamps.  One could build the whole thing for under 10 bucks,  under 5 if you have a friend in a machine shop. 

[gashousegorilla]

Both excellent thoughts gentlemen.Thanks.I actually toyed with the fork brace idea,briefly,before the swing arm mod. I've made one in the past, for a Honda shadow bobber I did, using 1" flat stock,bent in the shape of a "U". Two lengths,braced by 1" pieces,between the two "u" shaped lengths. Like a chequer board. Chromed it. looked good. Stiff as heck. I did it because "a proper Bobber has no front fender" Drilled holes in it, followed the contour of the wheel nice.I'll see if I can find a pic.
 But as scotty pointed out, and I did not even think of.the lack of a top fender mount
That's how I mounted the Bobber brace.Quinn, Like the idea of the cheap mock up with the muffler clamps, my only concern is the very thin ,1mm, shrouding, above the lower legs. check out your C-5, you'll see what I mean.I fear I will crush them.Also like the fork brace pic you posted, is it from JC?
The handle bar mod is probably not thread worthy, It was just a matter of welding on 2 1/2" extentions on the stock bars. Cut off and old pair of cb bars.
Come to think of it, why I was thinking about a fork brace,was because I met a guy up in Connecticut a couple of months ago, Who also had high speed stability issues with his Triumph Thruxton.He did all kinds of suspension up grades, and the last thing he said he did, was to put on a fork brace, which he said cured his problem. He was upset at spending all that money on Olin's shocks, steering damper, etc. Then getting a relatively cheap fork brace. I guess I chalked it up to a cumulative effect at the time?
Thanks boys, good work and keep thinking.
Dan.
Sorry,no close up of the Brace.
Come to think of it ,I also made a hidden fork brace, under the cafe front fender of a sportster chopper I did. Same configuration as the bobber.But again mounted to the top fender mounts. 13" longer in the legs,43 degree rake. Believe it or not, the bike handled pretty good. It had a Seeger cycle front end on it, for correct Rake and trail combination.No raked trees, but a pivot arrangement in the lower tree.Made in germany, very ingenious.
Sorry, I digress.

[ScooterBob]

Hmmmmmm - A FORK brace ...... Perhaps you guys are on to something here ..... Let the cobbing up process BEGIN! 

[Ducati Scotty]

Oooooooooo.... forgot the fork shrouds   Without those you might as well get a G5. 

I would say though that if you're going to do an ugly clamp mock up, weld it and make the cross brace as wide as possible.  Bolting it together won't make it very rigid.  Also, put some thick sheet material under the clamps to distribute the load so you don't pinch the top of the outer fork tubes.  They're thin and it's easy to crack them if you get to vigorous just removing the seals.

Scott

[qgolden]

Yup, I forgot about them too.

The pic I posted was just a google images find. 

[Ducati Scotty]

Hmmmmmm - A FORK brace ...... Perhaps you guys are on to something here ..... Let the cobbing up process BEGIN! 

Hey what are you?  Some kind of mechanical voyeur?   Wait, I think that kind of describes all of us.   Talk about the pot calling the kettle perverted!

Scott

[qgolden]

Scott,
Speaking of perverted which rhymes with converted,  are you going to be changing your handle to C5 Scotty or G5 Scotty soon?

[Ducati Scotty]

What?  That doesn't rhyme at all!  

Besides, it goes against my general rule of never wearing the t-shirt of the band your going to see and never wearing the gear with the name of the make/model you actually ride.  I think it's the full Harley starter kits people buy that turned me off to it.  You know:  the brand spakin' new ain't even broken in yet combo of Harley branded bike, helmet, shirt, vest, jacket, sunglasses, pants, boots, gloves, plus all the same for the wife to ride your 112dB noise maker three miles to the coffee shop waking up everyone within 8 blocks to sit there and drink lattes for 6 hours with the other 'bikers' and then ride 3 miles back home until the next sunny Sunday.

But I digress