Motorcycle Repair: 1985 cr 500, cr 500, air leaks

Question
I am having trouble with a cr 500 I cant get the main jet right no top end could it be something else. Magneto, cdi, coil?

Answer
I know nothing about 2-stroke MX machines, but if you have decent compression, I would check the spark timing CDI box to see if it isn't advancing properly. Otherwise, check your expansion chamber/silencer and exhaust port for being plugged up. Be sure that the carb is clean inside, set correctly (float level) and that the intake manifold doesn't have any air leaks. Pull the exhaust pipe and look into the exhaust port, checking the piston for seizures or stuck ring issues.

Bill Silver