I am in the process of installing a 734BBK and was instructed to replace the cam and oil pump chains. When I pulled the magneto off I noticed these heat marks on the starter wheel gear. I am guessing that the heat marks are part of the manufacturing process since nothing else looks to have any marks. I would think that if the magneto got that hot it would have caused damage to other components also. I am just trying to get some insight before putting it all back together.