I’m try to time a 66 XLCH and to get it right in correlation with the advance timing mark on the flywheel the magneto body is touching the rear cylinder push rod tube. There is no further room to retard the mag for starting because it’s already touching. If I jump one tooth clockwise it hits the air cleaner. I don’t know what’s in the motor but even if it had 1000cc flywheels the 5 degree difference in the marks shouldn’t change location that much. I’m thinking one cam could be a tooth out possibly. Interestingly enough the front cylinder compression is slightly lower. Tested the rings and they seemed good, pulled the head and seated valves with no noticeable difference. Maybe the cam is holding valve open at wrong time. Something is out and I’d rather not completely disassemble the motor without an idea what to check and a plan in place. Any help is appreciated.
P.S. the bike runs ok but is near impossible to start.