Super Jet Motor is out. What to check for?

Andersschroder

Andersschroder

Location
Denmark
Pulled the motor to get the cylinders bored for a fresh set of pistons. I will of course pressure check the motor.

Anything else to check/measure/inspect/change while it is apart and out of the ski? I wanna overhaul this thing as good as possible.


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Tyler Zane

Tyler Zane

Open Your Eyes
Location
Panama City Beach, FL
Ring gap and squish! If i where as far as you, id split the cases for new seals and check the crank for excessive rod end play. Id also have the head sent out to get shaved for a little compression bump or go ahead and grab an ada head.
 
Andersschroder

Andersschroder

Location
Denmark
Got it. Ring gap and squish how do i check that and why. The pistons come as a kit with matching rings (prox piston kit 81.50mm). And cylinders will be bored to 81.50. So it should be plug and play or am i missing something?


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john zigler

john zigler

Vendor Account
Location
wisconsin
On another note, I have become crazy fussy about engine / drive alignment any more. Typically they are off, even new from the factory. Get a Cold Fusion alignment too, and check yours. You start with the pump / drive, then midshaft, and final engine couplers. I do this on all machines anymore when ever I have the engine out. Your Splines, and midshaft will be MUCH happier, and live longer.
 
Tyler Zane

Tyler Zane

Open Your Eyes
Location
Panama City Beach, FL
Nothing is plug and play in our sport man.

Rings should be inserted into the cylinder without piston (use piston to push ring down 3 inches) and then measure the ring end gap with feeler gauges. Spec should be on the box of the rings. Should be around . 018 in. I always go on the high side on the range. This gap allows for expansion.

Squish, read this- http://www.x-h2o.com/index.php?threads/squish-questions.2681/

Rod end play is the amount the rod can move side to side at the wrist pin end. Should be less that .028 in if I remember correctly (don't have the manual on my phone). It can be done with the crank in the cases but I recomend cracking them for new crank seals. You will need a dial indicator for this.

100% agree with John, realign everthing. Read this. http://www.x-h2o.com/index.php?threads/squish-questions.2681/
 
Tyler Zane

Tyler Zane

Open Your Eyes
Location
Panama City Beach, FL
I have no idea why I can't say f33ler gauges....

All in all, people just throw top ends on all the time with out doing any of this. Does it work? probably alot actually... but these are all things that your professional engine builder looks at , plus more. Your machine shop has to know the piston size your using and the piston to cylinder wall clearance for said piston. Each piston manufacturer has there own clearance.
 
Andersschroder

Andersschroder

Location
Denmark
On another note, i need a complete gasket kit for the motor. Yamaha oem gaskets are they way to go as far as i understand, as i then need to order them all seperately. And i should stay away from sbt. Or whats the dealio on this, any other brands that are good/shidd?
 
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