1986 Suzuki RM 250 Right Hand Crank seal
A customer brought this bike in for repair because it is running terribly rich and fouling plugs. I immediately assumed it was a carburetor issue, and I did find some clogged jets and orifices in the carb that did contribute to the rich condition, but soon found out it was something more than just the carb. The amount of black goo coming out of this bike was more than I have ever seen on a 2 stroke. So bad in fact that the rear tire looked like someone had sprayed it down with “wet-tire”. Also, while testing the carb work I had done, the bike started smoking something fierce with the smoke being white and smelling like burning oil and not the typical blue premix smoke. After doing some research on thumpertalk.com the symptoms lead me to believe it was a failing right-side crank seal.
Fortunately, for this repair you do not have to split the cases. The clutch, water pump, primary gear and a few other misc. stuff must be removed, but nothing too complicated. Of course, with this being a 24 yr. old bike, any disturbed gasket had to be replaced.
With the new seal installed, the problem is corrected. There is still a lot of residual goo coming out of the pipe just from the old rich condition, but the bike does not foul plugs anymore and runs and idles the way it was meant to be.