98 SummitX 670

[msta999]

Hi all, great forum!
Question: I bought the above machine that was not running, but only has 2200 miles on it. I put the new up dated starter recoil on it and some new plugs. I noticed it has a little bit of a miss or rough idle so I did a compression test and I got 75 psi on the left cyl and 60 psi on the right side. That sounds way too low, but then I haven't worked on many 2 strokes. Does this sound like it is going to need to be rebuilt? I did take it on about a 10 mile ride and it seems to have good power, but keep in mind, this is my first snow machine:face-icon-small-fro

 

[ak]

That is way low try another gauge. Been a long time since I owned a 670x but I thought compression was in the 140 range near sealevel.

 

[winter brew]

I agree, try another gauge to be sure. Not sure it would run very good if that reading was accurate. Pull until pressure doesn't go any higher.

 

[Mafesto]

They can run good with sub-par compression.
I had 670 (non-HO) lock up on me. Let it cool down and put on 110 more miles that day to finish the ride & it ran very strong.