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Hi can any body tell me what the compression should be on the engine.
I have 90lbs in the center cyl. 85lbs on the outer two, does this seem to be low? burnt one piston and replaced it and new rings in the other two, but compression seems low,my be time for a bore job.
 

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XLT600sp you should have around 125 lbs of compression across the board. 85 to 90 lbs is pretty low. It may be time for an overbore. Riley
 

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Usually, anything under 100lbs of compression won't even run. 125lbs is about middle of the road (average compression for an older/used sled) once overbored you'll probably see 140 to 150 lbs....
 

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hows it run,if it runs o.k.,, try a different tester,should be around 120-125,even with a rebuild
 

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Not true larry. The older Polaris sleds came new with 125 lbs of compression. Boring a cylinder doesn't raise the compression over what the sled had new. Polaris never liked to have too much compression on their sleds because they didn't want to replace pistons when people ran sh-t gas. Riley
 
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