94 polaris650SL

[ravkev]

I have 120psi in two of the cylinders and 90psi. in the other, can i pull the barrel off and replace the rings to get the compression back, or what do you think i should do.

The motor seems to run pretty good, haven't had it on the water yet.but,
Its the back cylinder that has the lower comp. and when you gas it, It spitting a little out that carberator as well .

[ShowMePro1200]

Re: 94 polaris650SL

Not enough info for anyone to give a really good response - why do you have 90 in the one cylinder? Did you pull the head and look to see if there's a hole in the piston? If it is a hole in the piston top, most here would tell you that yes, you could do a top end job, and yes it will work, but the aluminum from that hole went to your crank and is going to do nasty things to it eventually. Could blow tomorrow, next week, next year....timebomb. Chance you take.

Something caused the low compression, and if you don't solve that in your fix up you'll be back where you started at some point in the near future.

[ShowMePro1200]

Re: 94 polaris650SL

I haven't had enough coffee this morning to be ansering questions - I just realized that if you had a hole in the piston you'd have ZERO compression. Sorry. I should know better, I been there, done that on a 750 SLT.

Still, you need to diagnose what is the low cylinder coming from. If its just the years of use, you could do a top end - I'd do them all while you're in there.

[SP]

Re: 94 polaris650SL

is that cylinder plated? US Chrome does a good job.

which cylinder did you loose the MAG?

inspect for galling of the cylinder from water leaking at the head or exhaust manifold too.

if the rear cylinder lost compression check the rear seal by doing a compression test on the motor, if the crank seal leaked it could have leaned that bore.