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Engine rebuild question

2K views 0 replies 1 participant last post by  ridethedoo 
#1 ·
I have a 96 Ski Doo Mach Z 779. On the weekend I noticed while I was out riding that the Oil injections lever adjustment screw had come unscrewed and the engine was getting very little to no oil. I don't know how long it was like this. I dumped in some oil in the tank to make it home. The next day I did a leak down test and here are the following results. Mag 80%, Center 40% , PTO 80% this was with a warm engine. Last night I did a compression test Cold here are the results Mag 135Lbs, Center 120Lbs and PTO 135Lbs.

This is something I have never done but plan on doing myself. I am hoping I only have to do the rings and pistons. Well I hope the rings only I am going to check the clearance between the piston and cylinder wall I hope it is within spec I believe is .003 to .005 thousands. and then check for taper and out of round on the cylinder. Am I correct in saying this?

How can I tell without taking apart the bottom end if I need to do that aswell?

Also am I reading this right or am I way out to lunch?

Thanks for any help or advice.
 
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