Super Jet Dilemma, to rebuild or build?

[Zimm]

Ill stat off with I bought a SnSj with a seized 650. Came with another 650 lowerend that is in decent condition.

Im attempting to building a surf/frestyle ski on a "budget". Putting my money into reinforcing the hull right now. But my question is it worth it to rebuild the 650 motor and wait till I have the $ for a 701? I know I would rather just drop in a 701 but the only ones I've found are mid to high $1000's or more and I just dont have that kind of $ haha. Any ideas or help of any kind would be apreciated! Im about to start the build thread here in a few days too!

 

[chriselmore_1]

Buy some 61x cases(701) you can usually find em fort 75$ and get a 61x top end. I think extreme throttle sells one ready to run with fresh pistons for 400$ use your good 650 crank and spend 70 bucks on gaskets/seals and your good

 

[snoproyo]

I would buy a core 701 top end one for $32 right now on e-bay, buy a 1.5mm top end rebuild kit $134 on e-bay, have someone punch out the cylinders $80-$100.

You would end up with a 727cc super jet for $240-280 bucks depending on shipping.

 

[Zimm]

Is there a big difference betwee the 6m6 61x case and the 701? Is extreme throttle a member on X or is it a shop? whats the differences in a 701 crank and a 650? or is it just the size of the piston that changes the volume? Im sure all of this is posted somewhere already, but after reading a couple hundred threads everything starts sounding the same haha. I apreciate all the help! oh one last thing are the heads interchangeable from 650-701.

 

[iangdesign]

This was outlined nicely in another thread a few up from yours.

6M6 is a 650 platform, small reeds, single carb 650.
61X is a 701 platform, single carb, better reeds and intake setup
62T is also a 701 platform, dual 38's stock, different reeds, and most will swear it's a better starting platform. I've got a
61X Jetworks 5mil stroker that is pretty nasty, and my 950 dasa 8mil stroker is also just as nasty. All depends on your riding style, what you want out of the motor, and what kind of riding you'll be doing.

Avoid 6m6 setups, even tho they're capable of handling a 701 topend, too small of an intake tract.

I believe a 64x is pretty much identical to a 62T, but with dual 44's stock and dual pulse fittings on the cases. I may be wrong, but pretty sure. Hot ticket seems to be a 62T bottom end with a 61x cylinder as the porting and exhaust port height differ. Most freestyle boats are running a 61x or billet cylinder, with and without powervalves. Just depends on manufacturer.