Join Date: Feb 2010
Location: Albany, OR, USA
Question.... Is it a wobble felt from the rear or from the front of the bike?
BTW :: Got my '88 K100RS back from my attorney and took if for a 486 mile one day ride this last weekend.
Reason I ask is because the feeling coming from one end of the bike or the other makes a great starting point to look for problems. Over pressured tires cause problems if they have been run too low on pressure and develope the odd wear pattern. (i.e. feathering, cupping, chop, and of course ridging due to wear on the outer edges and less on the center.) Also watch the tire pressures cold and not hot. Air expansion on a hot run then topping off actually leaves you underinflated. Tread depth differences change steering geometry and can make a bike feel a little wobbly.
Worn or mis-adjusted rear shock can cause problems. Too tight will cause the rear to push around on uneven surfaces. Too loose and the back sags thus taking the bike out of it's engineered suspension geometry. Fork springs worn out do the same thing. Worn fork bushings can cause the front tire to track or pull. Low/un-equal fluid in the forks will cause individual fork response different. (Thank God BMW puts fork braces on the tubes from the factory.)
And the steering head bearings being dry and/or loose can cause a wobble as well.
I found it best to start at square one with my K100RS when I got it, and make the mileage at time of purchase my start point for services and maintenance. Clymer has a nice schedule to follow for tires, lube, and general maintenance. I guess what I'm trying to say is perform as many of the checks and maintenance items as possible and see how the bike handles from there.