Originally posted by Scott Fisher
How can there be a performance advantage. They are the SAME. Only the tuning and maybe a little luck in terms of parts fitting will make one different from the other. The only thing I can thing of is if my memory serves me correctly, the NSR has a 9 fin head and the JP has an 11 fin head. This will make a difference to those that use stock cylinder heads.
FYI : Good news for you.........the latest NSR12S5 engines have 11 fins too ( I saw it at my LHS which imported novarossi recently ).