First off, I'm new to this forum. I have a 03' PRO-X 600 and i'm wondering if anyone has had this problem. The sled ran great the first year, although I only put on 275 miles. Last year, first ride, sled ran like crap!!! Wouldn't idle, backfired, no rpm's. The dealer re-jetted it and it ran ok. To make a long story short, this has happened several times. It seems the PTO side is running lean, even seized the motor once. Currently to get this thing to run ok, the jetting is staggered on the two cylinders. Main 450 PTO side, 440 MAG side. Needle 3rd pos. PTO side, 2nd pos. MAG side. Pilot 3 turns outs PTO side, 2 turns out MAG side. Have talked with polaris and they are talking about replacing the motor. Nobody has been able to figure out what is causing this, my only thought was an airleak though none has been found. Anyone with ideas???

Thanks in advance!!! :banghead:

Sure sounds like a air leak to me. Be very careful. It shouldn't get that lean.

Could be carb boots leaking, restricted fuel to the carb, crankshaft seal failure, or the crank itself is out of phase...the seize could have made that last one even worse. A good dealer should be able to figure it out in no time.

MANY 2003 prox 700 and 800's are running jetting leaner then 450! Why would your's have such large mains in it? I know for a fact a 700 can live with 420 mains at 0*f all season ! 430's if its -10! Is this what you have done to make it run or did the dealer do it? Sounds like the tune is way off! Set it to factory specs and see what it does.....

I am guessing they jetted it really fat to hide a real problem like a burn't piston or something with the crank. I had an XLT that I bought and the jets were so fat It was a bear to start and keep running. I tore down the engine and had a small hole starting to burn through by the exhaust port. There was an air leak and to try to hide it and fatten it up so it wouldn't seize just until they dumped it on me. Yes, it was a learning experience.

"00 and "01 motors were identical with the exception of small changes in ignition and fuel car calibration. The "02 uses a lighter flywheel and ignition. The "03 changed to a 18 degree timing offset to improve warm starting. The "03's also had coated pistons and different carb calibration and cdi. "04 motors use a different crank which incorporated a 909 water pump gear for accelerated coolant flow. Its recoil starter is also slightly different to accomodate PERC. The VES arangement was already covered. Subtle casting changes to the cases and cylinders are ongoing to enhance strength.

yup!!!! i run 450's with a pipe and head on my 700... also had 420's down to about -20 on a stock machine...

You got a big problem.

Who jetted it to that spec? If it was the dealer you need another dealer.

It does sound like an air leak like someone already pointed out. Crank seal, air boot, or the like. Were the carbs ever cleaned and setup right since you bought it? It could be as simple as gummed up carbs.

This thing is not even broken in yet, it must have sat unused for quite a while? Possibly rusty crank and rod bearings that are now so tight the thing is making too much heat just keeping it moving in there as well as a lean condition from gummed and or plugged jets?

You need a competent dealer/mechanic to assess whats going on or this thing prolly won't survive.

Those sleds are rock solid, this is likely caused by the above and or somebody wounded it before you got it.

Glad to hear from you guys, this has been frustrating to say the least! Yes the carbs were cleaned, both I and the dealer took them apart. They were completly clean. The sled was bought brand new, was there when they took it out of the box. Guess I picked the wrong box!!! All jetting has been done by the dealer, and the current jetting got it to run good. I agree this jetting is way off, can't wait for the new motor. I take it in Nov. 2nd :banana: Polaris can use this motor for a boat anchor. All my other sleds have never had to go back to the dealer, then this one. I do love this chassis though, IMO the best Polaris has built to date.

Thanks again!!!

Cool...Glad to see Polaris is backin you.

This is a great sled and you're right about it being one of the best they have ever made.

Post how you make out.....POLARIS or DEATH!!!

Imagine that 450's!!!!!!!! i had my 600 down to 350 once last year, i would say i could have brought it down to 320's for a quick race, that's a lot of feul!

Too bad your dealer isnt too bright and its going to cost Polaris a whole new motor, when a competent one would have been able to find the problem. Oh well, as long as you get it running again.