- Reaction score
A worn chain and/or front guide can change the timing on you but the way yours keeps on changing even after you reset it may point to a different issue, maybe with your advance unit. The advance unit is located by a pin in the cam. This locks it in that correct position so the timing is right. If that pin has fallen out or the advance unit has come loose, it may be moving out of the correct position, rotating on the cam instead of turning with it, throwing your timing off again and again each time it moves.