2005 Polaris RMK 800 Liberty VES

[Hrdwrk3r]

Hoping someone could point me in the right direction. My daughter rides A 2005 Polaris RMK 800 liberty VES. We have had no issues at all with the sled until recently. We were riding along and the snowmobile lost power, had a very large backfire, died, and has not started since. I had a little bit of time today so i started looking into it. I pulled each speck plug and they did not look any worse for wear. I checked the compression and only had about 30 pounds in both cylinders. I went ahead and pulled the head expecting the worse but the pistons looked great and there was no scarring whatsoever in the cylinder heads. It did look like both rings on both pistons seemed extremely loose compared to my 800 dragons. I did notice what I thought to be an unusual amount of dark/burnt oil under the magneto side of the orange rubber boot when I pulled the exhaust valves but no excessive carbon build up. At this point I would probably suspect one of the carburetors, stator, or something else electrical but honestly I have no clue where to start. I like to tinker but I am certainly no mechanic. If anybody has any suggestions I would greatly appreciate it.

 

[whoisthatguy]

30 psi? New engines have 150 psi. Nicosiling old cylinders and adding new pistons and rings can get you up to 145 psi. 30 psi is essentially crap. You might have a leak in your compression tester. If your tester is good, then you need a new top end. If a small girl can pull start this 800 RMK, then for sure you need a new top end.

Now as to where to start.
1st. The primary suspect is the coil finally gave out completely. Swap with an entire air box, CDI and coil from your other 800 RMK to test out, or remove the coil only from that other RMK and temporarily connect it between the CDI and the plugs. Buy after market on EBAY because they are way cheaper than OEM.
2nd. Temperature gauge may have gone out. Unplug it and insert a U-shaped wire in the two ends to connect them, of the main harness plug that goes to the temperature gauge on top of the cylinder. It is time to replace it anyways so you can buy them cheap off of EBAY.
3rd Your fuel pump probably needs rebuilding so you buy a rebuilding kit off of EBAY and change out the diaphragms without putting any creases in anything. It is pretty easy. But that probably did not cause the problem.
4th Either get the manual and run a stator test or buy the cleanest used stator you can find off of EBAY for no more than $75. You will also need a flywheel puller to replace the stator
5th. Some people say the regulator over the left toe box, goes out. I just have never seen it. If you have gotten this far then you are an expert mechanic, so buying a used one off of EBAY and replacing it will be no big deal.



The sled probably also needs new driveshaft and rear track bearings if it has over 2500 miles. These are work horse sleds that are relatively easy to fix by yourself. But they have to be maintained diligently.

 

[whoisthatguy]

This thread should be on the Polaris / Edge forum.