Snow coming soon... NEED HELP!!!!!

[ddog96mn]

So there is quite the storm coming and my sled doesnt run, its a 1997 Polaris Super Sport 488cc with Mikuni 34MM carbs, it runs but very poorly. i was riding it around my yard a few weeks ago, and it was running great, all of a sudden it started bogging like crazy, and wouldn't move with a load on it. so we got it up to our shed and took a look, so far we have "fixed" the fuel pump (put a fuel pump kit for it. (round 2 port Mikuni fuel pump)) we've also cleaned the carbs and made sure the floats weren't sticking, couldn't tell if they were before but they shouldn't be now, also put new spark plugs on it. so tonight we fired it up and it did the same thing, it didn't idle fine, but an eighth of a throttle kept it running at idle, (pretty boggy all the way through) then accelerated it to about 3500 rpms and it really started to bog down. not sure what the problem is but would like to get it solved so i can ride for this storm, so if anyone could help me i would greatly appreciate it. Thank you!

 

[mike_s]

Pull the carbs off and look into the intake throught at the piston skirts. (im assuming this is a piston port engine, and not reed valve) if one or more of the pistons skirts are broken it will run very poorly, or not at all. Is there excessive spray back through the carbs when the engine is running? This is another signal of a broken piston. Some blowback is normal, but it it is more than a light myst then you have issues.

Also, watch for any pieces of aluminum or grey colored coating on the plugs, yet another indicator of piston issues.

 

[ddog96mn]

Thanks for the reply, I did do a compression test to it, both cylinders tested to 135 PSI, I do believe that it is getting too much fuel for some reason, could it be a jetting problem?

 

[miller tools]

sounds like bad gas drain it out and get new take the tank off get it all out

 

[ddog96mn]

Thanks, I syphoned it all out and put 5 gallons of new gas in it, still runs the same.....

 

[mike_s]

Thanks for the reply, I did do a compression test to it, both cylinders tested to 135 PSI, I do believe that it is getting too much fuel for some reason, could it be a jetting problem?

Doubtfull being it happened so accutely. If a skirt is broken it will still show good compression. What happens is it looses all the tranfer pressure (crankcase pressure) because the piston does not close the intake port anymore. Causing the engine to be hard to start and act incredibly boggy, as if to be running rich.

 

[ddog96mn]

I will have to check that, it does start easily though, could it be something with the main jet?

 

[ddog96mn]

It was the Skirt, well that sucks, thanks so much for the help