Thanks for your answer jmuddin284! Unfortunately, for that particular model (ATP 500, 2004) the needle jet and jet needle are not available, see the microfiche.

The first dealer I went rebuild the carburator with Sportsman 500 parts and the first ride I did after, the engine started backfiring until it died probably because It was running to rich. The engine only did this when I was running 40mph going up on hills for a while. So, I went back to this dealer and they told me that the needle jet and jet needle could not be pruchased separately for this model. They called Polaris and used Scrambler 500 parts instead. It worked for the rest of the summer last year. This spring, I took my ATV for a ride, and it started doing the same thing. I went at another dealer and they wanted to rebuild the carb with Sportsman 500 parts but I told them to forget it and that I would instead buy the carb assembly because I'm sick of this. Now, I have my ATV back and I'm looking for information before spending 315$ + shipping!!!

I think I'll call Polaris... Thanks for your help.

 

I appologize. You're right, there isn't anything on any of the microfiche I've looked at for what you're needing. I haven't had time to try to look it up, but MOOSE may have an equivalent aftermarket setup. You could also check out ebay for a used or even new carb, or call around to some local (non-branded) repair shops to see if they might have something laying around that they have kept for parts or what-not. Or you could try the carb companies website or call them and see if they can help you out. Just a couple of ideas for ya.