I own a 1998 600 EFI powder special with about 2,800 miles and lately it hasent been performing as well as it used to while hill climbing. I just had the primary and secondary clutches overhauled but it seemed to make little difference. I believe it may have something to do with the EFI because it has fouled plugs the last 3 times out which has never happened before in the past. Is there a diagnostic test that can be performed on the EFI cats?
well if you haven't done so already check your compression if this ok then have the pressure regulater checked,don't forget to check the reeds!!!if you have a broken reed this will afect your compression check. good luck!!!