Motorcycle Repair: gas fouled plug, stupid thanks, gear case

Question
hi mike , i asked you a question about rear cylinder only gas fouled plug only last week.i should have explained a little better. i did check the coil and wires ohms before i wrote you. i have been putting basket case sportys together as a hobby for many years, since 60's.i literally got this one out of barn where it had been for some time. the first time i turned it over there was zero compression in rear cylinder. took it apart ,there was 1/4 inch of carbon holding exhaust valve open. glass beaded it , lapped valve in , good compression. but it still fouls and i am totally stumped. is it possible the previous owner put no.1 and 2 cams in wrong and it would still have good compression in that cylinder, maybe just a tooth off, because to me timing is all that's left. and electrcally it's good. so could the valve timing be off is my question to you . sorry for being so longwinded. i don't mind taking gear case off ,just getting kind of old to be down on floor that long if i'm doing something stupid. thanks a lot . randy

Answer
Since you only hae one cylinder that is fouling, the cam cam be off, if they were removed so I would check it. Since you tested the coil and wires the other things it could be, valves to tight, leaking valve, leaking intake.
Good luck and happy riding
Mike