Head shim + rebuild

bustamove

Active member
Nov 1, 2010
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Alright so from the top, I bought a 09 nytro 163 mtx6500km/4000miles, with what I'm told is a mcx 240 kit ready to go. Unfortunately I got screwed, got it home it sat for about a week or so went to start it up. Long story short, exhaust pumping out burnt coolant oil level is milky and over filled now. Hopefully rod isn't Bent, and crank is okay(can't tell clutches are so god damn noisy)

My questions are:
With the head shim is it an oem gasket above and below it? Or 1 gasket split apart, research has me more confused.

Should I replace head shim? With stainless or mcx aluminum? Pro and con to each? I emailed mcx and they want almost 200 cad for a new shim. Yet hurricane +others want 75usd ish for stainless.

Every bolt on this engine is torque to yield. Obvs head,rods, bearing caps, I'll buy new. But can you reuse the case bolts? Well we're talking about bolts are arp worth the money?

From the research I've done usually head gaskets go due to overheating or really pushing way to much boost. Anyone heard of a cracked head or block? My worst fear!

I'm coming from a polaris rmk 900, jury is still out if I'll like the nytro or not so I don't wanna sink a whole bunch of money into yet... but id like to get it running.
 

MTN_VIPER

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Nov 26, 2007
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fourstrokesolutionsllc.com
Since it has coolant in the oil and you have no way of knowing how long it was ran in this condition. I would go ahead and pull the lower case (oil pan) and rod/main bearing caps to inspect the bearings. These engines run tight bearing clearances (usually around .001") and if the oil is contaminated or ran low on oil it can damage the bearings fairly quickly.
If there is bearing damage and you try and run it, there is a chance that it could spin a rod bearing and pitch a rod through the side of the block. Normally it's the center rod that lets go first.

It's probably not the answer you wanted to hear, but I would pull the motor to do the tear down/inspection. As it sits now you have a rebuild-able engine and by tearing it down you'll know for sure if it's sound before spending more money on it.
 

stingray719

Well-known member
Jan 22, 2008
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Colorado Springs, CO
Since it has coolant in the oil and you have no way of knowing how long it was ran in this condition. I would go ahead and pull the lower case (oil pan) and rod/main bearing caps to inspect the bearings. These engines run tight bearing clearances (usually around .001") and if the oil is contaminated or ran low on oil it can damage the bearings fairly quickly.
If there is bearing damage and you try and run it, there is a chance that it could spin a rod bearing and pitch a rod through the side of the block. Normally it's the center rod that lets go first.

It's probably not the answer you wanted to hear, but I would pull the motor to do the tear down/inspection. As it sits now you have a rebuild-able engine and by tearing it down you'll know for sure if it's sound before spending more money on it.
Having done a few I agree completely with this.
 
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