Wrong Engine Parts! help!

[ksw144]

So I just bought a '95 sportster project boat. It's just the single engine, which was bad. Anyway, pulled the motor, sent it to a guy who's rebuilding it. Well he told me it had the 717cc motor...

After ordering a new crank, pistons, and base gasket, I was told by the guy doing the cylinder bore work that the pistons are too big.

I just did some research, and discovered that I actually have a 650cc motor, NOT the 717cc... ugh.

SO, what I'm wondering is if there's any chance that the crank is the same in both motors. That's going to be my biggest issue I think with replacing parts. It's a hundred bucks to ship both ways, plus I need the proper one.

Anyway,

Thanks

KW

 

[timmyboy76]

aint say'n it would work/crank align within case...but, the "stroke" is the same for both 657/717 motors, but the bore is different...657=78mm, 717=82mm.

If you cant drill it out, then maybe a 717 sleeve, but thats up to mechanic/machiine shop. Cant see why not, considering, there's "big bore" kits available, using smae cylinders.

 

[timmyboy76]

rv timing..159* valve

i'd time it at 147* opening, 65* closing to start, then if not working, set time, for what the 657 calls for.