FML SOB compression gauge

[Jesse_01]

So I check the compression on my 2012 Turbo pro 300miles, it's reads 100psi each side. I have a big weekend of sledding coming up starting Friday. So I bust my ass and pay $100 shipping to get pistons here for this week. Pull the top end off tonight and everything looks like new. So either it's the rings or my compression gauge is f'ing me. Either way going with a Terra Alps kit. I was amazed how easy it is to tear a pro down. I should of tool pics a long the way. I can take some putting it back together.

 

[96sherm]

What method did you use for checking the compression? I've been told by a few different people, all competent/knowledgable mechanics that how you check compression will affect what reading you get. I've also heard that guages can vary in reading quite a bit. I check on a room temperature machine, throttle wide open, 5 pulls-reset guage, 5 more pulls-record reading. I have 3900kms on my '11, compression checked out at 100/110psi. I pulled it apart for a visual and will also be re-doing the top end because of some nasty piston/cylinder scoring on the PTO side.

For reference, my buddy's '12 was sitting in my garage so I checked his compression also and with 1200kms on the clock, his machine pulled 120psi.

 

[gedakbx]

My 2012 at 3400 ft had 125psi at 400 miles. I have one gauge that reads 15 psi lower than the other.

 

[Jesse_01]

I did it cold and warm, with throttle wide open and closed. Got the same reading all 4 times.

 

[Jesse_01]

Either way I will have new pistons in and will test it than to get a baseline.

 

[j335]

I've read new pro's having low 100's. these sleds have real low compression. Either way you're putting in better pistons now, can't go wrong.

 

[HotShotHarry]

11 pro-2800 miles-100psi each cyl-cold-@3500 ft. 1 cyl had 4 corner scoring and a nick out of the sleeve. New pistons and cyl required.

 

[96sherm]

Do yourself a favor and inspect your bottom end crank seals and bearings also Harry... Your condition sounds like what I had recently... I'm going to end up with a totally new/rebuilt motor...

 

[channonmanuel]

Just checked mine 420 miles on 2013 turbo pro 100psi per hole what's the polaris spec?

 

[Jesse_01]

Just checked mine 420 miles on 2013 turbo pro 100psi per hole what's the polaris spec?

I was told 125 psi. That's why I changed my pistons out. I should have them in tomorrow now and I will recheck to get a baseline.

 

[Jesse_01]

So I put new pistons in and got 125psi. Took it out to McBride, made it 3km up the trail and the voltage regulator f'd me over. Sob poo poo.