tune up? ignition is preset hence cdi , so unless you have a snapped woodruff key on the crank there aint anything wrong with the timing, if their was the exhaust would be glowing, due to spark advance or retard, and seen as their is no mention of the engine being to pieces, then their would be no reason to believe the timing had not been set at the camshaft correctly, bob might wanna rethink his advice, this is a compression fault
m, January 2013