Hey guys and gals,
I have a 97 yamaha bruin and the oil cooler line busted causing the oil to dump out. un Fortunantly it was at night and wasnt able to see it before the bike died. It has fire and compression. What else could it be timing? Fuel? Oil pressure? That is keeping it from cranking again.

 

I would be very surprised if you do have compression. Most air cooled Quad engines suffer from piston and/or piston pin seizure when run short of oil, it can wear the cam/followers excessively too. Anyway, the piston starts to pick up on the bore and the result is seized/broken rings, a "milled" piston, and a big gap that compression can leak out of. Incidentally it must "crank" or you couldn't check for a spark, it just doesn't fire.