I haven't payed too much attention to the Kawasaki 600cc engines lately. I have spent a lot of time with the 1000cc motors however. The older 600cc motor had a bore/stroke of 67mmx42.5mm. They simply increased the bore to 70mm's to achieve 636cc's.
In the new 636 motor ol' Kawasaki decided to get the 636cc number by increasing the stroke, it dimensions are 67mmx45.1mm coming up with 636cc's also but giving the motor more low end grunt for the street, and probably making a better TQ choice also.
I have not read the rule book, but in the face book they state that the 636 package must remain stock bore and stroke dimensions.
What If>>>a guy started off with an older 600cc motor. They had a bore of 68mm's back then. Kaw tends to stay pretty much alike with internal dimensions. What if a guy dropped a late model crankshaft down into the older block. I haven't been inside one of these motors but knowing Kawasaki it probably would fit. Now you have a 600cc motor that been increased to a bore and stroke dimension of 70mmx45mm. Very close to 700cc's.
Would that be legal?
Honest Dad himself
