I recently bought a xr200, it was low on compression but still ran fine once you got it started and kept the rpms up. Ran good, went to start it back up, had to keep the throttle wide open to keep it going and would just barely say running with it wide open. held it wide open thinking it maybe had got flooded but I finally let it die. When to kick start it a few minutes later and it's locked up, can't kick it over. Now this is my first fourstroke and need a heads up on tearing into it. I will be tearing into it in about a week and I'm hoping it just needs a bore, piston and new cam chain. I've never ever worked on a 4 stroke before, and i'm hessitant about the cam chain and valves. Any pointers? Do you think it's just the top end or could the crank have gone out?