657 and 717cc?

[Bent]

what were the differences?
(no, I don't mean just displacement.)

I'm curious as to whether one was the 80 hp engine and one was the 85 hp engine...

near as I can tell, neither one was RAVE equiped.


The '95 speedster shows as having two 657's
The '96 speedster shows as having two 717's

 

[robin savell lloyd]

From what I understand wich I could be wrong but let me try and explain. The 657 has 70 hp and the 657x has 80 hp. the 657x has been ported differently than the 657. This diference can be seen on the rotary valve port. the 657 has a round port and the 657x has a slightly larger oval port. the 657x allso has a stronger crank case than the 657. [kind of like a 350 chevy 2 bolt main and a chevy 4 bolt main engine] More beefier botom end. not exactly but simaller. The 657x is supose to be very close to the 717 which has 85 hp. With the beter porting of the 657x and the 717 I believe that the hp may be close but the torque will be very different than the 657. both the 657x and the 717 performance would be a lot beter than the 657. the 657x and the 717 are all most identical. :cheers: