coffman Pipe on 750sxi

[anthonystempak]

You have to take off your cylinder and put it in a vice and hone up and down straight l would guess ,youtube it

Theres a torque spec for the base bolts should be like 18ftlbs and harbor freight.com sells Pittsburgh torque wrenches that work for 10 bucks about as good as a husky torque wrench

I belieave you will be at 145psi for a minute , you have to break in the rings

 

[anthonystempak]

My ski wont run right at 120psi

www.kenoconnorracing.com/portingtemplates.html
You need a dremel tool

 

[anthonystempak]

9-17 skat

 

[anthonystempak]

Im thinking your pipe is more of a ported pipe,typically they run a slightly smaller diameter of expansion chamber larger more power

Your motors toast

 

[Ryan Stewart]

Well hopefully its not toast. That might be a bit early to say. I havent tried it now that im back to stock pipe and tsr box and original jettings and turns on screws. Guess well see. But, worse case is i just have to bore it out a bit right?

 

[bandit88]

Ryan,
Please do not listen to anthonys/timothys, his advise is all BS. Compression specs on the 750 motor are 110-155 psi. Your 135 is fine and depending on your elevation, may be the reason for it. Obviously more is better but you are well within specs. For a impeller for a stock/near stock get a Solas Concord 9/15. Nothing wrong with a Skat 9/17 but the concord will keep it hooked up better in choppy water.

 

[Ryan Stewart]

Thanks! And they are straight forward on installing them? Big improvement on performance? If not, ill just leave stock. Will i need to adjust jet size im guessing? I but some destoryer tubbies on the side already. They feel like worlds better than stock hull.

 

[bandit88]

Impellers are easy if you have the tool and a vice. It will be a improvement over stock, but the condition of your stock one will determine how much.

 

[anthonystempak]

Rebuild the topend ,and the pipe and stock waterbox,you should do the crank seals they must be leaking a little ,theres a pressurization test