Help with a CR80
 

I was hoping someone could help me split the cases to my sons CR80. I have some new oil seals to install and gasket kit. The problem was oil getting from the clutch to the crankcase and getting shot out the exhaust so it was smoking like a bugger. I have the right and left case covers off but can't split the rest because I don't know how to get the magneto off piston seperated. Anyway anyone with any knowledge on this process, I sure could use some help here, I might be in over my head.

Do you have the service manual for the bike ?
Without it you will be fighting what should be a relatively simple task.
Flywheels are held on by a keyed taper and will have to be removed using a puller. (Don't be tempted to hit the flywheel with a hammer or to pry it off with a crow bar)
Sometimes a simple bolt with a single ball from a ball bearing is enough, but the manual will tell you exactly how to do it and even provide the part number for the puller.

Kai Ju