I feel your Pain! I have a 96 Sportsman 500 with some of the similar problems- mine will idle fine just has no power . Bought it used, never seemed like really had that much power always lost it on topend, or just going up hills etc, but got worse. So at first thought must be carb! so took apart cleaned it (many times), diaphram was marginal so replaced it, fuel filter replaced checked all vent hoses air box for leaks etc took fuel pump apart there was plenty of dirt on the vent side cleaned it, thought that must be the problem, but made no diference. tried another carb off another machine ran the same! so since then!

1) tore it down checked exhaust lobe was within .001 of new dimensions, rocker arm looked good no unusual wear.
2) pulled the black wire off limiter like u suggested above no diference.
3) made sure elc throttle control was not causing problem.
4) tried pushing reverse bypass switch while acceelratings no diference
5) tried putting on choke while accelerating, wanted to die then.
6) sprayed carb cleaner around carb while running checking for leaks no diference.
7) ran fuel with a direct line from gas tank to carb by-passing fuel pump made no diference.

Anybody else have any other ideas please tell me!

 

Double check the cam the 500s are known for that, also check for moisture in the fuel

 

Sagjan,

I am back from hunting and stopped by my cousins motorcycle shop, they sell and work on Polaris machines. I talked to their mechanic and he seems to think that if the oil was not changed much then the problem might be the worn exaust cam lobe. They also told me to check timing that it might not be right. So this week I am going to get to work on it and hopefully solve this problem. I do not know if you checked your clutch but the one I am working on had a broken spring so I pulled the clutch apart and have been trying to get motor running right without the clutch on the machine, So i am going to see if not having a clutch on the machine has something to do with the rev limiter as tommorow I will put the clutch together and put back on the machine and see if that does anything. Lets get to work!!

Rungunner

 

go for it rungunner...i hope you find a solution..i sure havent.

 

Sgajan,

I pulled the cam out. The exaust lobe is not on the cam anymore. It is supposed to be the same diameter as the intake lobes. It is almost flat. This is the problem with the machine I am working on. Did you pull the cam out of yours and check it? It is very easy to do.

 

holy crap ..im gonna have to tell him to check his....you say its easy?..that sounds good..im taking it that that lobe should be raised quite a bit?
?

 

I figured you guys had bad cams but I assumed you knew how they should look, the exhaust and intake lobes should look nearly identical. If the exhaust valve doesn't or barely opens you'll get what sounds like a backfire in the carb when trying to rev the engine, the noise is the exhaust pressure coming back into the intake when the intake valve opens as it can't get out anywhere else.....

 

Sgajan,

I ordered the new cam today, Not bad at $185.00 and if you find that the lobe is gone like mine you better have him buy the rocker arm also because that will be worn and cause damage to the new cam. I have never seen a cam go bad like this on any Honda I have worked on. I hear a few Suzukis, Yamahas and of course Polaris sometimes do this from lack of oil changes according to my cousins part manager. Let me know what your cam looks like you will really see it if the lobe is gone.

 

Rungunner.. i will have him replace his if its bad. He drives truck so hes out alot. but when he gets back i will tell him. Let me know how it goes will ya?.thanks and good luck

 

how do you change the jet needle clip to make it more lean or more rich?