1990 zzr 600 oil leak
 

Hi all, I have a problem with my 1990 zzr 600d, the clutch shaft? (pretty sure that's what it's called.) goes in at the bottom of the clutch case and there is currently an oil leak. It is very slow but I'm worried about getting some oil on my tire or the oil possibly catching fire on the exhaust. I've looked up diagrams, replaced the gasket, and even just taken it all apart and looked for cracks. People say that it requires an o-ring there but I haven't been able to find a replacement nor a diagram suggesting so. Any help would be huge! Thank you.