77 yahama 360 runs for a while then sounds like it vapor locks. Pulled the carb, removed the bowls, and thetops. Looks pretty clean. Needles are a little dirty and one of the cyllanders is a little dirty but nothing major. Ideas? The engine feels very dirty where the intakes are have not opend it up. I have not worked on a bike before so language may not be right. Sorry
Motorcycles - Yamaha - DT 360
Answers & Comments
When the bike develops this problem, check your compression on both cylinders, if it is low you may have a "sticky" valve on the cylinder head.
If not the carbs on that bike are vacuum carbs and you may have some small perforations in the diaphragms. The other thing to check is, that bike is pre CDI so it will have breaker points on the ignition system, check the gap is correct. These older bikes can also be prone to having rust flakes in the feul tank, so a good modification is to put an in-line feul filter between the tank and the carbs, as there is a very fine jet in the carb, behind the main jet, that when blocked will not allow the bike to rev above an idle.