Instability on C5

[BRADEY]

Guys I own a 2010 C5, which becomes very unstable at the rear swing arm, on speeds above 60-65 MPH. However if I crouch down chin on tank, the instability disappears only to reappear as soon as I am upright.

In my opinion this bike has serious aerodynamic issues, and mechanical instability at the rear swing arm. Does anybody know of any corrective measures being taken by RE to address this issue.

I am afraid to say this, but this bike is not road worthy at high speeds. 

[ScooterBob]

This has been a complaint for a few - and it just about ALL comes down to proper chassis set up. The bike was designed with razor-edge geometry to be a CRISP handler and any deviation from perfect will induce a high speed oscillation. Take the bike back to your dealer and have him check the wheel alignment, tire pressure, head bearings and the set the angle of the bars as low as they will go and the problem that you experienced will most likely go away.

[BRADEY]

Whatever may be the changes RE made to the rear swing arm of this bike, I don't care. I don't want a rajor sharp CRISP handling bike, that can't even use the entire power range available from its engine.

All I want is a bike that is stable and balanced, and not one that shakes as if some kicked her in the back.

I would go on to say so much so, that if I could plant this engine on my old frame, I can beat a "factory balanced, aligned and the works" new chassis with my old one. No matter how "Crisp" she may handle.

[qgolden]

Bradey
I think Scooterbob was saying that there is a more than likely chance that something is out of spec on the Bike Chassis, that is giving you the issues.

Mine, and most of the C5's here handle  safely alone the recommended speeds range.  Bearing in mind it is a light bike and depending on the size and shape of the operator, handling at higher speeds will vary from rider to rider.   These Bikes are not marketed and sold as high speed machines, and have a maximum top end of around 85 to 90 I do not think you would ever see an RE as an 80 MPH Canyon runner without serious modification.

Get it back to the dealer and explain your issue, and request that he test ride it. Something is out of whack and needs to be fixed. The bike as designed is very stable at 65 MPH.

[ScooterBob]

Bradey
I think Scooterbob was saying that there is a more than likely chance that something is out of spec on the Bike Chassis, that is giving you the issues.

Mine, and most of the C5's here handle  safely alone the recommended speeds range.  Bearing in mind it is a light bike and depending on the size and shape of the operator, handling at higher speeds will vary from rider to rider.   These Bikes are not marketed and sold as high speed machines, and have a maximum top end of around 85 to 90 I do not think you would ever see an RE as an 80 MPH Canyon runner without serious modification.

Get it back to the dealer and explain your issue, and request that he test ride it. Something is out of whack and needs to be fixed. The bike as designed is very stable at 65 MPH.

You are right here - although the C5 is quite the departure from the "traditional" pick your nose with one hand and steer around the potholes with the other RE handling. Perhaps a G5 would have been the better choice for Bradly as it retains the steering geometry of the Classic Bullet. That machine was built for TOTAL stability - even when overloaded. It's the "truck of choice" in lot of parts of India just because of that fact.

[Sub]

I think what you're experiencing is normal. I did 65 for the first time the other day and a brief wiggle of the bars created an unnerving oscillation. The bike is just not designed for it, and I'm ok with that. If I need to do highway, I'll take another ride.

Frankly, if it were good, it would lose some of the charm and character this bike possesses. To be honest, character is the main reason I bought this bike.  I dont think anyone at RE expects this bike to be a high speed demon or even able to keep up with modern bikes. However, on a back road, doing 50 through twisties, it is quite capable.

[ScooterBob]

Here is an interesting link describing motorcycle chassis oscillation. Note that EVERY motorcycle has a resonant chassic frequency!

http://www.vf750fd.com/blurbs/vibmode.html

[gashousegorilla]

Come on now Guy's, that's a little bit of Monday morning Quarter backing , for those of us who are having this issue.And it seems not all are. And in all fairness, last year they did market the new UCE with higher speeds. Definitely a deciding factor as to why I bought it.I wish I had bought the G-5. The dealer did not put me on a scale, and measure my height, then say, " Ya know what, Ya better get the G-5  if your ever gonna get on the highway and do some real world riding". And I'm not even sure it has anything to do with weight or height.This is a bike being marketed in the U.S. with all our major highways. Maybe there's  bad batch of frames out there?I don't yet Know for sure what it is.
 Remember, Before  my swing arm mod, with the bike aligned correctly, 18" front wheel, Head bearings adjusted correctly, all motor mount fasteners, all fasteners checked, tire pressure, etc, etc. A bone stock bike, I started loosing stability at 60 mph.
    I consulted with my dealer,who is no longer a dealer, and head mechanic, who had no Idea and gave me the honest answer that he had only worked on RE's for two years. My other option is to take it to the next closest dealer witch is 6 hrs of traffic hell round trip. To be likely told "everthing looks fine".Look, I ain't an RE expert but as scotty so kindly put it, I ain't no slouch.Something is amiss.And as you guy's know, I have gone above and beyond the average guy and been pretty positive about it.
  Look, I think one of the reasons guy's like Brady and me are on this forum is because it is are most accessable link to the company and the experts. Also the people with vast knowledge on these bikes. All great people and also a deciding factor in purchasing this bike.You know I heard comments from people, not here,that the C-5 is just "an old Mans bike" and " is really just for cruising around on back country roads". B.S.!!!!
  So lets figure this out. What are our options. Sell the bike to the next unsuspecting soul? Trade it in for a G-5? Sorry, I like you ,work hard for my money and am not willing to take a Loss on a sale or a trade.
 Dan.

[r80rt]

Here is an interesting link describing motorcycle chassis oscillation. Note that EVERY motorcycle has a resonant chassic frequency!

http://www.vf750fd.com/blurbs/vibmode.html

Interesting link, thanks Bob.

[ScooterBob]

Here we have the proper recovery technique for a gentle high speed oscillation. Notice the rider gets out of the saddle to add weight to the front suspension to settle the oscillation. Next, he shifts his weight to the right side of the bike to counter the weave - and then pops back into the saddle to motor off happily!

http://www.youtube.com/watch?v=6Fa0GmdSN4A&NR=1

Enjoy!

[CMB]

Dan,

I'm with you. Luckily my local dealer has a C5 demo bike that I was able to ride on the freeways out here in Southern California. Once I hit 60 and the rain-grooves the front end started shaking - and then the rear started oscillating too. Back-off to 55 and everthing is fine.

I would love to own a C5. Given the choice of looks and remaining alive, I'll take the G5.

I hope you can get things sorted out with yours. My dealer thinks the fork bracket will work.

Cameron

[perri]

I write from italy, c5 are the owner of 2009, confirm the earlier instability

sorry for bad english

[gashousegorilla]

Thanks Cameron, I hope it works, I'm running out of options. Same experience here with my bike, minus the rain grooves. Starting to see a pattern? India, U.S. Italy. Maybe we all need video riding lessons?

[TheFatMan]

You guys are making me nervous.  I am 5'10 and 230# (the fat man).  I have not encountered this resonant wobble at any speed, but haven't beat 65mph yet.  Is this on all of em?

[r80rt]

I've never experienced it on mine either, I wouldn't worry about it.