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Discussion Starter · #1 ·
First off let me start out by saying I don't know the reason for this problem yet but I am starting to lean toward RKT making some machining mistakes. As part of the 734 kit, you must install the new pistons then bring them up to Top Dead Center and measure the difference from the top of the piston surface to the cylinder/Head mating surface of the cylinder. Then you are supposed to call RKT and give them this measurment so they can cut the domes accordingly. This measurment has to be taken directly above the wrist pin on the top of the piston as close to the edge of the cylinder as possible. The mag side piston measures .0115 on the inside and outside edge directly above the wrist pin.
Here is the problem: The PTO side piston measures .008 on the inside and .019 on the outside. Too clairify, If I were to bolt the head on and check the squish with a peice of soider, it would be .011 diffence from side to side measured parallel with the wrist pin. As I turn the clutch and the piston travels down, it is easy to see that all of the piston to Cylinder wall clearance is on the .008 side or inside of the piston. On the other side, the piston is right up against the cylinder wall.

The other problem is even more strange. None of the original head bolts will thread down into the cylinders far enought to tighten down onto the head. After 8 to 10 complete revelotions they just start to tighten up and have a 1/4" or so to go yet before they even touch the head.

Now I know I am not the smartest engine builder out there but this is not the 1st snowmobile engine I have rebuilt. This one is driving me nuts. What the heck should I do? I put 3 calls into Kelsey at RKT today and got vmail each time. The last one I was not very pleasent. I will be posting pictures of this engine around 10:00 am Eastern time 1/8/05.

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