Thread: Low Compression
07-10-2012, 08:50 PM #1
- Join Date
- Jul 2012
I recently bought a 2002 Polaris Virage at a very reasonable price. The seller fully disclosed that the reasonably price was because the center cylinder had low compression. Cylinder 1 and 3 has a compression of 130 psi while cylinder 2 is at 85 psi. I took the ski out this past weekend and rode it for about 15 minutes. It seemed to run well, I got it up to 50 mph before I let of the gas. My questions are, how big of a problem is this, can the ski be used in itís current condition and can the center cylinder be rebuild while leaving the other two as they are. Any help would be greatly appreciated.
07-10-2012, 09:21 PM #2
07-10-2012, 09:31 PM #3
With good compression in all 3 cylinder you should be around 57 mph.
For each revolution the piston makes 2 strokes, 1 up 1 down, so at 6,500 rpm there're 13,000 strokes the piston has to make in a minute. The ring expands as it enters ports in the cylinder then compresses as it passes, 13,000 times a minute. Low compression piston probably has its edge melted. Piston ring could be exposed, not fully contained in the groove. If it catches edge of the port and snaps, you could be looking at not only replacing the piston but cylinder, head and even crankshaft as well.
07-11-2012, 05:01 AM #4
- Join Date
- Feb 2012
Yeah I agree with everyone here, if you had 110 PSI or something maybe its just worn rings, but 85PSI? something is pretty messed up, not sure of the price but you could probably get that center cylinder fixed up for less than $400, I wanna say even $300 but I don't wanna lie to you.
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