Hello,
I just picked up a 1997 Sportsman 500 that needed a lot of work for my wife to ride. The carb was totally gunked up which I thouroughly cleaned and it starts and idles fine. It runs great with the exception of when I come off wide open throttle, it idles down then it dies out. It doesnt do this when coming off 1/2 to 3/4 throttle. Only when I'm running it hard and let off the throttle, anyone have any ideas?

 

Maybe this it,s common. (click on top bar to view) http://www.ehow.com/video_4468404_polaris-atv-thumb-throttle-maintenance.html (click on top bar to view)

 

Thanks for the reply. I already checked the play and I unplugged the black wire from the RPM limiter to eliminate that. Neither had an affect.

 

If it at least idles when you crank it,could be starving for fuel or even loading up from too much fuel if you just cleaned the carb and didn't install a carb kit.Needle and seat could be sticking,float level may be off or could be leaking fuel around the seat o-ring.Also can be because of a pinched tank vent,just remove the tank cap and see if any change. Plus pull the fuel line at the carb ad crank the engine over.Should be a steady pulse of fuel. If it's a weak stream,could be a stopped up fuel filter or a weak fuel pump itself.Plus on this model not a bad idea on checking valve clearance .006 intake and exhaust,plus check for any wear on the exhaust cam lobe. This was a problem on a lot of early 500s.

 

Thanks Old Polaris Tech, I took the fuel cap off to see if that would change it and there was no difference. I will check the fuel supply tomorrow night to see if it's the fuel pump or filter. If not, I will move onto the other things you suggested. I suppose I should have put a carb kit in it but everything looked good so I figured I was ok. I will report back tomorrow night.

 

I figured I would post an update. I checked the fuel flow and it was strong while cranking the engine. I pulled the tank tonight and adjusted the valves to the specs on the manual. There was no change so I ordered a carb kit. I'll put it in when I get it and let you guys know what happens.

 

I got the carb kit and installed it and readjusted the float, it's runs great now after coming off wide open throttle, thanks Old Polaris Tech!!! I do have one other question though......There is a chatter coming from the recoil side when idling. I pulled the recoil and greased the starter bendix and it stopped the noise. However, after running it, the noise came back. I assume it's the bendix and I checked the bushings all around it, is the chatter normal?

 

Chatter happens usually when the bendix starts to wear out.Grease will help for awhile as you've found out,but doesn't last.Look close at the bushings again to make sure they don't need replacing also. Look over the recoil to make sure the 10mm bolt is tight and recoil functions properly,no loose,worn parts.Stretching the bendix spring usually doesn't help plus not advisable. These things are cheap enough now just to throw the old one away and install a new one. Plenty of cheap ones on ebay($21) and other places. http://www.ebay.com/itm/Starter-Drive-Bendix-for-Polaris-Sportsman-335-400-450-500-1993-2011-/271468482155?pt=Motors_ATV_Parts_Accessories&hash=item3f34c84e6b&vxp=mtr