45 mph wobble

[Scott03]

Good day,

 

This past weekend I noticed a wobble at 45mph on my 2002 Lemans. It only occurs if I remove my hands from the bars. The ocsillation increases in amplitude, but can be stopped by replacing my hands. This does not occur at 40 or less or 50 and above. The bike is solid at all other speeds. With hands on the bars at 45 I can feel a little more vibration, but only because I started looking to feel for it. The tires have 3k miles on them and this is the first I've noticed the problem. Tire pressure was fine. So I am thinking to check ft wheel bearings, stearing head bearings, and swing arm bearings. What am I missing? Any suggestions or advice is appreciated.

 

Scott

[fotoguzzi]

Good day,

 

This past weekend I noticed a wobble at 45mph on my 2002 Lemans. It only occurs if I remove my hands from the bars. The ocsillation increases in amplitude, but can be stopped by replacing my hands. This does not occur at 40 or less or 50 and above. The bike is solid at all other speeds. With hands on the bars at 45 I can feel a little more vibration, but only because I started looking to feel for it. The tires have 3k miles on them and this is the first I've noticed the problem. Tire pressure was fine. So I am thinking to check ft wheel bearings, stearing head bearings, and swing arm bearings. What am I missing? Any suggestions or advice is appreciated.

 

Scott

tire balance, maybe you threw a weight off?

[Tom M]

In addition to checking all those bearings you might want to verify that all your engine, transmission & pork chop mounting bolts are tight. I don't know if it would cause a wobble but dragging rear brakes from a dirty caliper are common on these bikes too.

[GuzziMoto]

My Daytona did that at 50 mph. I replaced the tires (they were old) and replaced a missing engine mount bolt (from the previous owner) and the wobble is gone. My guess is that the missing engine mount bolt was the problem, but it could have been a tire/balance issue.

[luhbo]

It's just a tire thing. Remove or rise the pressure a bit and it will be different if not gone. Change to new tires and it will be gone also.

More here:

 

http://en.wikipedia.org/wiki/Shimmy

 

The whole thing stands still, only the front wobbles - and as soon as you put your hands back on it comes to a rest again.

 

That's shimmy, or wobble. It's harmless. EDIT: "should be harmless".

 

Hubert

[jrt]

Have you ever loosened the front forks? A wobble can also be caused by mis-aligned fork tubes, but I think this might manifest as a high speed (and dangerous) wobble.

Common to some old BMW's.

edit: woohoo (or sigh). this is my 4K post. Better change my oil.

[Skeeve]

Good day,

 

This past weekend I noticed a wobble at 45mph on my 2002 Lemans. It only occurs if I remove my hands from the bars. The ocsillation increases in amplitude, but can be stopped by replacing my hands. This does not occur at 40 or less or 50 and above. The bike is solid at all other speeds. With hands on the bars at 45 I can feel a little more vibration, but only because I started looking to feel for it. The tires have 3k miles on them and this is the first I've noticed the problem. Tire pressure was fine. So I am thinking to check ft wheel bearings, stearing head bearings, and swing arm bearings. What am I missing? Any suggestions or advice is appreciated.

 

Scott

 

Fairly normal for worn [cupping] tires. Brand new tires will make the problem go away [almost]; it's really always there, on every motorcycle, at various speeds [on my '86 Gold Wing, 35mph is the "magic" speed.]

 

Seriously, how often do you ride w/o at least 1 hand on the handlebars? Non-issue for most of us...

[rocker59]

It's a tire problem and common on most bikes.

 

What tire are you running? My Nero Corsa was bad at 40-45 mph with the Metzeler Z6.

 

With the Dunlop RoadSmarts, it's almost non-existant.

[emry]

I just chased this problem on an FJR about week ago for a concerned friend. He had installed a different brand of tires from OEM, rode about 1k miles and then noticed a "shimmy" when he took his hands off the bars.

 

My answer was don't.

 

But after running through many of the above suggestions, I swapped the tres out with another brand and the problem was gone. He was then satisfied that his bike was ok and that it was only the tires.

[gstallons]

I just chased this problem on an FJR about week ago for a concerned friend. He had installed a different brand of tires from OEM, rode about 1k miles and then noticed a "shimmy" when he took his hands off the bars.

 

My answer was don't.

 

But after running through many of the above suggestions, I swapped the tres out with another brand and the problem was gone. He was then satisfied that his bike was ok and that it was only the tires.

 

 

What brands were involved?

[Scott03]

Thanks everyone. I agree, the obvious solution is not to take one's hands off the bars. Tires are Conti Force - again, this is the first I noticed this issue in 3000 miles on these tires. Perhaps the front has cupped enough to now start doing this. I'll check the other items as well (loose engine bolts, bearings, adjusting tire pressue), but I happened to have coindidentally ordered new tires before I left on this last trip so hopefully I'll resolve this one way or another. Thanks again and I'll post with an update once I get back into the shop.

 

Scott

[emry]

Dunlop 252's were the ones that caused problems. Tried two sets. Metzlers and Bridgestones(OEM) worked without problem on all of the bikes (we have 4 Fjr's.) Although the BT's start cupping after 3k miles, just like the ones on my Guzzi did.

[stormsedge]

Mine was missing an engine mount bolt...the other was loose. I also backed off the steering damper a little. Keep smiling.

[Scott03]

I finally got around to replacing the tires and the wobble went away. I also found that the rear axle (spindle) nute was not tightened to spec. For now, I'll assume that the problem was tire related. Thanks. for the assistance.

 

Scott