Road shimmy

[LarryA_Texas]

I have a GS1100GK with new Metzler tires front and back. It has 12k showing on the odo. and appears to be in reasonable shape.

It's very stable when I first start to ride, but as it warms up it begins to shimmy like a high school cheerleader.

The affect is as if it's got a tire going flat, or maybe like riding on a rain-grooved highway. It's the lower part of the bike moving side to side at random...definitely NOT a vibration. It's too random to be to be tires out of balance, engine or drive vibration. It's also not side wind or other vehicle turbulence.

It's a workout to keep it going straight and can move (wobble) several inches in either direction at random. This isn't affected by speed, either. 30mph or 60mph feels the same.

Maybe bearings???

So here's the question. What's the best way to check for bad bearings?

Any other suggestions as to what it might be?

[bonanzadave]

but as it warms up it begins to shimmy like a high school cheerleader.

Thats an analogy I can live with.

Maybe bearings???

Steering head bearings. Youll have to re torque them with the big nut on top of the fork tree. I dont know the exact proceedure but I do know you must loosen the fork tube pinch bolts before you tighten the head bearings. While your at it give the front end a total once over from the tire pressure to the wheel bearings.

[KiwiGS]

What size is the back tyre? Is it the right size?
I had the same thing happening on the wifies bike. Turns out some numbnutz had put a too wide tyre on it. Put the right one on and the shimmy was gone.
Just a thought.
Cheers

[bwringer]

Also, check the swingarm bearings. They're extremely durable tapered bearings on shafties, but put it on the centerstand and see if there's any play.

You could also have a defective or damaged tire. It happens.

Steering stem bearings are the most likely problem, though.

[LarryA_Texas]

problem solved

Thanks for the tips. When you said steering bearings I assumed they needed to be tightened. That didn't help and may have made it worse. Thanks to TKent's suggestion, I went the other way and loosened the top nut a bit. Problem solved.