I have used K n L kits on many occassions, and have had decent luck with them. I was told by someone here, that a petcock kit by them is imprecise and should not be used. I specifically searched another forum, and some over there on xs11 say that K n L jets are no good in the carb kits, that its a must to use mikuni jets, which is what I thought were in K n L kits. Apparently the xs11 guys, say original mik jets are the only ones to work right, what say all yeeee. Has anyone else had a lot of experience with the blue envelope brand, prior to this my experience s with them ended about four yrs ago, has something happened in the meantime to cheapen their reputation????
Echoing what Daniel told you, the K&L kits do not contain all the parts that the OEM kit does.
My own experience is that the K&L kits don't last as long as the OEM kits.