I have a 500 that will replicate EVERYTHING you say here if the airbox lid is loose or off.

Did someone lose a gasket or any wingnuts? Is the airbox gasket seated correctly?

I juiced mine down with silicone grease and replaced all the wingnusts with 300-series stainless after greasing all 10 or 12 bolts. The idle smoothed out considerably, and the response has ZERO bog.

They were designed by VERY smart guys. See if the design has been altered.

If you have bad backfire through the carb an intake valve is open while the engine firses.
THAT is a serious problem. Serious. If it is mildly choking-up while th aircleaner and lid is off this may just be the nature of the beast.

D

 

crank it up in the dark and look around the plug wire and coil and see if they are any sparks coming from them. a bad plug wire will make it backfire.

 

Twoblackbelt: so if your air box is off or loose the motor wont even rev enough to engage the belt or move the bike?? I tried the spark in the dark thing.. I got nothing ..thanks though.

 

Sjagan,

How is it going with your problem? FYI My machine idles great with air box lid on or off, It is not an idle problem as that is the job of the pilot jet. It has the same problem no matter if the air box lid is on or off. Do you get more backfire in reverse? I got my manual today and the new jet needle and jet and am going to try that this week and also unplugging the switches on the transmission one at a time as it is running. If none of this works it is probably one of the exaust valves not opening correctly thus backfire through the carb.

 

Rungunner: Im not making any progress. It doesnt make a difference wether the air box is on or off. Let me know if the jet thing works. Does the book give any insight as to what it could be?

 

If the motor is running the way you say it is..now matter what...in or out of gear...then your problem is something else...electrical. could be a sheared keyway on the flywheel, or a bad cdi or coil. could be a lot of things. if you honestly believe it is the carb...then it could have a bad seat somewhere...or chances are it is too rich somewhere... i had a 400 and the motors are identical...my problem was that it was running way too rich...i had a 175 main jet in it though, and the needle was at the wrong height.

hope this helps

Wes

 

the motor will not rev high enough for the drive clutch to even engage..no power at all. bike wont move..reverse or forward. I just dont know what electrical it could be.. i was told that if the cdi is bad then i wouldnt get any spark at all...... but the bike does start and idle. I adjusted a needle to the highest spot on it ...didnt help though.....sigh...thanks though

 

Yeah, it'll engage and run, but absolutley horribly.

It sounds like at idle it has enough vaccuum to keep fuel delivery going, and as soon as you take it off idle it dies, eh? Sounds like fuel delivery to me, but I'm a "hands-on" mechanic, and do not know this machine well enough to troubleshoot a trouble I've never had without the thing in front of me (or underneath me; or vice versa).

I think yer going to have to bite a bullet and find a Polaris mechanic unless you live in South Central Utah!

 

Try running it with the gas cap off to rule out a tank vent problem, shoot carb cleaner in the carb throat when trying to rev it. That will tell you if it is a fuel starvation problem. It may have a bad stator.....

 

powerslider..it dies if i spray start fluid in the carb..i tried the tank vent already thanks. Twoblackbelt...this bike wont even move...not even a bit..could be fuel ..but where. Thanks...this guy might have to bite the bullet for sure..i kept telling hime dont mess with anything because he is for sure a tard when it come to even tying his shoes...he tride prying off the flywheel and busted the magnets rather than use a puller...250 bucks later..he had a new one