One odd thing is when I retarded the timing when I gave it more throttle the timing would go more retarded than advanced not sure why.Bike wont even run at all unless it is on that 15 degree mark that is shown on the mikesxs install. So I am not sure what to think. Its just depressing. I am not the person that has the money to drop this off at a shop and can work on a car all day long but am stumped when it comes to a 1977 xs 650. Just dont have a clue. I am still hoping with this new timing chain and guide that she wont heat when it warms up around this area. I am going to have to run it at the timing marks that the bike decides to run at and hope for the best. For all I know the engine was built or worked on that didnt do justice to the rings and who knows what else.