Help with 1993 R100 GSPD

[ARP]

Last night I rode about 40 miles. Nothing out of the ordinary. Today as I was leaving the driveway the bike had a side-to-side wobble in the steering. I pulled over assuming the front tire was flat, but it wasn't. So I continued slowly and it wobbled or shuddered at low speed. So I sped up a bit and it stopped....and seemed to go away and not come back.

 

I needed up riding about 100 miles and cursing at 55+. No problem.

 

But what caused it ? I need to start diagnosing. Any ideas ?

 

I should say the bike only has 23K miles and is as perfect as can be. It has newer Wilbers shocks and springs and I recently came back from riding LA to Mexico to CO and Chicago.

[Dennis Andress]

Put the bike on the center stand and support the engine so the rear wheel is off the ground. Grab the rear wheel at the back end. Push and pull the wheel while holding your finger across the gap between the swingarm and the frame, feeling for movement between the two. Do the same with both hands at the top and bottom of the rear wheel, looking for movement between the hub and the final drive.

 

Support the engine to raise the front wheel off the ground. Take off your tank bag, if you have one, and any farkles attached to the bars. Stand in front of the bike and move the steering using the front wheel until the wheel is pointed straight forward. Moving the steering back and forth a few degrees feel for a soft notch in the steering. Anything attached to the bars, cables, brake hoses, wiring, will make any notching harder to notice.

 

Change the fork oil. True the wheels.

[Tri750]

Have the steering bearings checked as touched on above. That's a common issue.