It was running fine on thanksgiving, went back home for the weekend and now it won't start. It will sputter for a second but that's it. It has spark and fuel. It backfired through the intake a few times. Any ideas what could be causing this?

 

Other than cleaning the carb,the other thing I'd do is to check the exhaust cam lobe for failure. They can slowly wear down over time and people can think it's a problem that just came up.

 

Google "Polaris 500 ATV cam wear". It was a problem up until the H.O cam replaced it.

Here is a video on it.

 

Good video on the cam shaft problems the early 500s had. Like how this "good old Southern boy" talked about the soft heat treatment on the cams,but said not changing oil regular enough probably contributed a little to his problem.. Refreshing to see someone not blame the problem all on the machine,but put some of the blame on his own shoulders also

 

Thanks guys! I guess I better get busy I guess haha

 

My dads 97 SP500 had 5500 miles without the cam problem but he did oil changes and only used synthetic 0w-40 which helped on cold starts.

 

I also had a '97 Sportsman 500 with thousands of miles on it without any cam problems. I kept the oil changed at regular intervals.

 

Ive only had the four wheeler for a couple weeks now and the most I rode it was loading and unloading it from my pickup. I changed the oil as soon as I got it home with Mobil1 0 40 full synthetic. It ran fine before and after the oil change. I'm pulling the pull start cover off cause the rope broke on me the other day and I read that there is a key for the flywheel that may have been sheared so I'm going to check that while I have it apart

 

Yes that can happen also. The 500 was also bad about shearing flywheel keys. Hope it's simple as that..