I have been wondering, on a 760 there is a +4 stroke. What if you make it a -4 stroke instead? It would make it a 690cc on a 105.5 piston. What power characteristics would it have compared to the 760 with same compression and setup? Is the valve train a limitation? Would 15000rpm or more be possible? Is this type of build even a consideration or is bigger always better? (sorry Kyle)

 

I think 15000 rpm would be REALLY hard on $hit!! I don't think making these motors able to rev to the moon is the answer but what do I know.....[img]i/expressions/face-icon-small-smile.gif[/img]

 

Antwain w/the set up you are talking about it would be more of a 330ft quad...it seems like you would have a whole lot of torque...destroking the motor to -4 should make it around a 68?cc's..well you would not have near as much top end as you would if you were to go w/the 760 it would be more a low/mid range set up...but w/the right gearing and the right holeshot it would be killer...15000 rpms is possible....you just better have a rev limiter that will let you go that high...i just hope to god that you dont blow your motor trying to go that high of rpm..i would say more in the 12000/13000 range....

 

I think that would be a KILLER motor. But it would cost you a fortune to build right. I am not real up to date on the process, but I think it would be complicated to do considerring keepping the same compression ratio. You would need a custom piston, different pin height, and a shorter rod, I think???? Or possibly stock piston and shave the cylinder, and a custom length cam chain???

 

the guys who run in the nhra crate engine drag race class , destroke there motors and twist the snot out of 'em. but beleave this they spend far more on the lightening and balancing of the entire engine than the motor itself cost. but it can be done (how fast do you want to go and how much money do you have) think about forced induction if you want to go crazy fast, and not have to fill a n.o.s. bottle all the time!!