Reproduction cam chain tensioner for Honda CB750 from 68-78. As your engine runs the cam chain is spinning all the time and it slowly wears all of the parts that guide it and put tension on it. If you're doing your top end and you plan to replace the cam chain and it's associated parts, it's a good idea. Check for wear of course, but sometimes it's good to go by the "while you're in there" approach.
The cam chain guide is on the front side of the engine.
Replacement For Honda Part Number: 14500-300-000
CB750A Hondamatic - 1976-1978
CB750F Super Sport - 1975-1978
CB750K Four - 1968-1978