I've always been told that compression on a 2-stroke engine (any make) should be >120 psi. I've now been told that Polaris sleds may have less compression and still be fine, and that you can find the specs in the service manual. I have a 2013 PRO RMK 800, but cannot locate a service manual. What is "new" compression, and at what compression would you start to think there may be a need for a rebuild? Does anybody know the specs or where to find them for this sled?
And remember, cranking compression will also fluctuate with barometric pressure and elevation. An engine at sea level will develop more compression than a sled at elevation. So in Wyoming, you may be 110 psi and still be pretty healthy as far as the top end goes.
And as far as that 800, I would replace pistons at 4000 miles, that can save you a bunch of bucks. Polaris pistons seem to have weak piston skirts and when they break, they can do a bunch of damage to the engine.. been there, done that, don't want to do it again!!
Dan, what would be the average cost (CDN) of a top end refresh? As still haveing top end issues, bogs after 80 mph on the 04 600 edge xc, did carbs clutch cleaned etc, new plugs, sled works great starting after 3 weeks, just lost that extra zip on the lake? Heck my 05 600 tourer is faster lol) thanks
No idea on Canadian prices, you will need two pistons/rings/piston pin bearing, and piston pin. Also the cylinder base gaskets, and head O rings. Add a bit for misc parts and antifreeze. Here's a link to a parts site that lists Canadian prices, it may help guide you.
On the 600, when was the last time that the VES valves were cleaned? If the valves don't fully open on high acceleration, it will really zap the top end. You may consider replacing the springs in the valves if they are worn, too. Spendy little guys... (assuming compression is ok...)
Did the giltines in the fall all clean then but never thought about the springs, the rubber gaskets were ok also, oh well no sledding here for awhile, trails closed no snow 15c...
Hello snowmobilers!!!! I’m having some issues with my 2015 Polaris 550 Indy voyager! It’s only firing off of one cylinder! We just bought it and it went back to the dealer and got rebuilt but they didn’t do a great job the exhaust was melting the plastic the fuel pump wasn’t attached and the carbs were as black as anything. We just cleaned everything and re assembled it with what ywe thought needed to be done, yet it’s still not good. The compression on both is only 90
take that back to the dealer that did the work and get them to fix it. Also, be sure on your compression measurement, there are a lot of bad gauges out there. Take the reading on a warm engine with wide open throttle.
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