New to the site, and new to working on Kawasaki 250 bayou. I purchased at a ridiculous low price for a project ATV. The guy said it leaked oil like a screen door on a sub, and wouldn't start.
I got it, and put cam shaft, both rockers, top timing chain gear, and ALL new gaskets, EXCEPT cracking the crankcase, because it wasn't leaking there, and I didn't replace the alternator cover gasket. Afterwards, I could start it and ride it, but it smoked and the clutch slipped, so I took it back apart and put primary and secondary clutch in it, and new piston.
NOW it runs like a champ, and doesn't smoke and the clutch is jam up. But, now, its leaking oil out the alternator cover gasket, and when I removed the oil fill plug while the engine is running, the crank case has positive air flow coming out the oil fill hole.
In honesty, I had NOT checked for the presence or absence of positive air flow coming out of the crankcase, so I dont know if that's normal. So NOW it is such high positive air pressure in the crankcase, it is forcing oil out around the rubber boots that the wires run through coming out of the crankcase to the wire harness. But it starts, very quickly, and runs great. Can ANYONE offer ANY advice?

 

I went to Kawasaki repair shop and talked with the guy regarding my leak and where it was, and about the fact that the engine has SOOO much positive crankcase pressure while running, He echo'ed what the "merryman" said, these engines do have a large amount of positive air pressure, which is causing my oil leak. He sold me some "silicon gasket" in a tube. It is NOT your normal silicon in a tube, he told me to remove the alternator cover, and clean with brake cleaner REAL well, the rubber grommet that was leaking inside and out, and apply silicon, that should fix it. I will provide and update tomorrow, and let everyone know if it was successful.