Carbon/Duracon heavy duty cam chain tensioner cap for all years Honda Grom. One of the weak points of the Grom 125 engine is the cam chain tensioner design. From stock to all the big bores, the oem cam chain tensioner cap can wear through very easily and cause the steel tensioner to contact the cam chain causing premature wear on the chain and cam timing failure. Simple install, drop your oil, pop out the tensioner and replace the button with this heavy duty version.