I fitted Chris’s 300kit and couldn’t credit the difference 50cc to the bike, it’s a fast very capable bike and I would think with some suspension tweaking you would be faster on it in most conditions then on the 450, also the 300 wouldn’t wear you out during the course of the day like a 450.
As far as the 331 kit goes the engine is designed and built for certain loads and stress on components, the engine handles a 50cc increase because it was designed for it in the frist place. The increased stress put upon components such as piston, little end bearing, conrod, big end bearing and main bearings over a period greatly reduces life and reliability (ask Bana his DR has blown up twice)
The increase from 250 to 300 is incredible, but I think the old saying that some is good but more is not always better maybe worth considering, cost and stress on parts etc taken into play.
I keep thinking about those 720cc they sell in the states for my bike, but my bike has a HRC kit in it and that’s enough, truth is its more than I ever use or can if I was towing road trains I may do it, ha ha crash will tell you our 650 would pull road trains as they are.
TB
ps if you do it I would love to see the difference it makes, the 331 kit that is
