I have a 1990 zzr600d. There is a slight oil leak, nothing major, maybe about a quart every 2 weeks. My problem is, I don't want it to get on the back tire while I'm riding or the exhaust and catch fire. It's coming from the bottom of the clutch case where I believe that the clutch shaft? Correct me if I'm wrong please, enters it. It's happened for about 4 months. If I tilt it at enough of an angle it stops and it only happens when it's hot. A few friends said its supposed to have an o-ring there but I haven't been able to find a diagram indicating so or even a replacement o-ring listed. I've taken it all apart and replaced the gasket and checked for cracks. All seems good.