We have done a lot of testing on the Arctic Cat Z/ZR 120, Polaris XC/XCR 120, and Ski Doo MiniZ/Mini Rev 120 engines. We've modified them and have found the weak link to be the rocker arms, especially when using a different cam and heavy valve springs. To solve this problem we use CRYOGENIC treating to give the valve train strength. This can also be used on many other engine parts. For more strength yet, try our welded Champ reinforced rocker arms for the Ski Doo Mini Z/Mini Rev and Arctic Cat Z/ZR 120.
THESE ARE SOLD AS ONE PIECE, NOT IN PAIRS. YOU NEED 2 TO REPLACE THE ROCKER ARMS IN YOUR ENGINE NOW.