Difference in weight not be huge, but did you take the diameter into account? Weight further away from the centre of rotation is going to result in higher rotational mass.. This is just a train of thought, I haven't actually done the maths - but the 61X is a good 20mm(?) less in diameter..
certain stock race yamahas have been seen to be running kawi drive couplings probabily because they are far smaller and lighter. Doing that would probably be a bigger gain then taking 2mm off the side of the flywheel.
running wiseco prolites also the early hollow cranks Gun boring the drive shaft all that stuff is ok but i reckon its not the gain that every one thinks
you still want shit as strong as possible ay and you dont really need every last 1/2 a horsepower for surf riding haha ya just need an ol 650 and a good run-up!
Waxhead I am also porting my 61X cylinder at the moment off a 2008 superjet I am using the new racelogic template for porting which is different from the porting on the cylinder on this thread Can you tell if you measure 13mm down on the sleeve from the base of the cylinder or you go down 13 extra mm from the bottom of the sleeve?
The racelogic porting I am using is a newer one they have released, it is totally different to what is shown in this post. What extra porting work would you suggest I do for freeriding?
