Hello,

 I ahve a 1997 Polaris Sportsman 500 driving me crazy. In idle it revs up just fine but while riding it cuts our at about 20 mph. Feels like its hitting a rev limiter but at a very low RMP. Anybody else had this problem?

I have a similar problem with mine 2000 spman 500, I'm still diagnosing...

My symptoms:

1) rev limiter kicking in while in R, L, H at low to medium throttle.

2) reverse-override has no affect on rev limiter in any gear (and I shouldn't need it in L/H!).

3) reverse-overrride makes Reverse indicator light come ON when pressed and bike is in L or H. - testing demonstrates that this behavior continues even with speedo/sender, 4WD/ETC switch, and 4WD coil wires all disconnected.

4) 4WD works in forward gears as expected, and only in reverse when override button is pressed as expected.

5) cleaned/reassembled and bench tested switch box on left side handlebars (very difficult to reassemble) - all checks per book

6) checked front and rear tranny switches - all checks per book.

I'm at a loss.   You might see if #1 - #3 apply to you, if so, we have the same problem and I will share with you my fix once I get it.  If you already fixed it, PLEASE tell me what you did!

 Good luck!

UPDATE:  Looks like I got it going again.  Decided I'd take a different approach to see if it wasn't really electrical, and looked at the carb instead.

I changed my fuel filter which didn't help the situation, causing my float bowl to overflow and severely flood the carb, to the point the airbox has gas in it .  I replaced the float needle assembly since it didn't seem to be sealing now with the increased fuel pressure, and rebuilt the carb, adjusted float height.  It was DIRTY!  Mid/High jets were probably clogged and why the bike hesitated so bad at middle to high throttle.  The float bowl was stained with dirt residue in it.  Got my choke loose again too and readjusted so it works now - PITA to removed from carb body, I was unsuccessful.  After all this, there is no hesitation in throttle response through the whole RPM band.

I hate that I mis-diagnosed this as the rev-limiter, but I have to be completely honest that the instant missing and sputter was very consistent with the reverse rev-limit kicking in, in all gears around that specific RPM and up.  And the fact that the reverse light comes on when the yellow button is pressed and the bike is in forward gears I thought for sure it was electrical.  Anybody else have this light indicator behavior too?  Guess I could have put the bike in neutral to see if it sputtered there too when revving the engine.

Unfortunately this issue started right away after the Popo was put up for several weeks, without any warning or bad running symptoms previously like this, so I didn't think it was a fuel problem.

 I did discover yesterday after the carb fix, that in reverse the override doesn't kick in, it goes as fast as you want.  I've seen this on another Popo's every now and then, sometimes it works other times it doesn't.  But last time I check I still need to push the button for 4WD to engage in reverse gears.

 Hope this helps anyone.

Yet another update...  Looks like the actual problem since the beginning of all this was my airbox snorkle tube that sits on top of the gas tank, under the body plastics.  The bike started acting up again this weekend after I removed and replaced my airbox lid.  Turns out the piece of foam that holds the snorkle in place also serves to block the snorkle intake opening if you're not careful with it when pushing the snorkle lid back up under the plastics, making your life hell as you chase what you think is electrical and carb problems resulting from an engine gasping for air.

I was able to test and exagerate the engine sputter symptom by tapeing up the intake partially to get the motor to sputter and miss like before with only marginal throttle.  Removed the tape from the lid opening, put the lid back on making sure the piece of foam was not blocking the intake opening on the airbox lid snorkle, and now all is well.  What a PITA!