I HAVE A 97 SPORTSMAN ITS BEEN RUNNING LIKE s**t about half throttle its fine but when you open her up it just pops, now the steps i took where, cleaned the tank,cleaned and dismantled the carb 3 times check the spark plug,changed the exhaust back to stock changed the fuel pump. it idles fine,also about 5 min of riding under load the exhaust get cherry red at the manifold, all this happened after i got stuck in a 1 1/2 ft mud hole that took damn near an hour for me and my buddy to get it out that a different story lol does not over heat. so any ideas would be great to getting this bastard back on the trails!!!!!!

 

This means it is running to rich not burning all the fuel in combustion. fuel ends up in the exhaust. You may possibly have weak ignition. Did you try and clean out the stator? Allso may be ignition coil on the way out.

Some things to try. Hope it helps. I will let you know if I can think of any thing else.

 

If it was running rich he would not get the glowing pipe cause the unburned fuel would cool it. He is running a lean condition. You may have some jets in the carb or some air passage/vacuum line clogged with mud.

 

how did the plug look?? if its running red hot pipes its because its running lean, too much air ,not enough fuel to cool it. also the older sportsmans wear having cam issues acting like some of these issues wear the lobes would wear off and not letting the valves open which would make it run hotter as well. imo.

 

I guess you guys dont rember when cars had carburators and the choke would stick and dump fuel and the exhaust would glow red hot.

 

yes sir i do remeber back in the 70's were i have seen it happen but pretty sure that isnt the issue on his wheeler at this time.

 

Could the muffler be blocked? If that is not it, and it is idling fine, and running fine at 1/2 throttle, I would suspect it is running lean.

As already suggested, how does the plug look... fouled (black) or lean (whitish)?

 

the wall thickness of the exhaust is very thin and glows when running. Pull your wheeler in the garage and run it with the lights off, the pipes glow.
As far as the poping, I say it could be lean at the main jet.

 

Hot pipes mean lean, look at the year of this 500 fellas. Personally for FYI I would look at valve lash and inspect the cam. Those things were known for the exhaust lobe wearing off. Then go at the diaphragm in the carb, make sure all of that is free. I'm thinking this might be two issues on this thing.

 

this is why i mentioned this=(also the older sportsmans wear having cam issues acting like some of these issues wear the lobes would wear off and not letting the valves open which would make it run hotter as well. imo.
i also agree that if a bad diaphr. could be the issue. good call for sure.