A forum for owners of Yamaha TTR250 trail and enduro bikes!

Just a quick tip for when you are doing a spot of TTR maintenance. Check that the one way valves are working. I have just put a carb back on a TTR I am working on and thought I would check them - both were blocked! Not unusual in my experience. 

Just pop them off and check you can blow down through but that when you blow the other way they shouldn't let any air through. Very simple job to wash them through - and blow out with an airline if you have one.

I don't think that blocked valves would have any effect on the carb running because the pipes are still open where they attach to the airbox mount. You just don't want them filling up with water or gunge and allowing that to go back into the carb.

Brian