Thankyou

 

Interesting, I was talking to a guy re bike water temp recently and he warned me not to run my bike with the rad cap off as the system is designed to work under pressure. Pressure raises the boiling point so IF your running the bike with the cap off then any air lock will lead to boiling water or as the other guys suggest a duff rad cap will prevent the system from pressurising. Maybe check the stiffness of the pipes when the engine is up to temp obviously they should be stiffer than when cold, if not look for leaks or consider a cap replacement? Good luck mate.