First off I am no mechanic, but My 6X6 Ranger started running really Bad. By Bad I mean bogging down Backfiring especially when you try to give it gas. It won't go more than 10 or so MPH and won't climb onto its trailer, but it will run and idle. I would be happy to take it to the dealer and get it fixed, but they are like 3 weeks or more behind. I changed the fuel filter, air filter, spark plug, pulled the carb and got it rebuilt, still same thing. About the only thing else I can think of is the electronic ignition box. Anybody have any other suggestions. Thanks in advance.

 

May I ask what motor is in it and what year it is???

I had my friends 96 500 Magnum motor do the same thing your describing. It turns out that when Polaris made the cam, they didn't make the exhaust lobe oil passage big enough, and it wore down due to lack of lubrication. I ordered a new cam (which has a bigger passage) with exhaust rocker arm (all about $300) and it runs like a top.

 

Its a 99 Model although it says Manufactured October 5, 1998. Its one of the 2 Seater utility vehicles with a bed. I am sure they only put one type of engine in that model. It was top of the line when I bought it. I use it for work.

 

It is a 500 CC motor. Thats about all it says in the manual. Doesn't say anything on the Papers

 

My friends was a 425 not a 500, I typed before I thought, sorry. Have you tried a compression check to see what the compression is. I don't think that defective cam applied to the 500 motors, just only the 425's. Test your compression with a warm motor, and open throttle and see what it reads, that will tell a lot. Plus open you gas tank lid and see if it will idle up normally. Just trying the little and simple things first.

 

I dont know much about the Ranger line, but if they are similar to the quads it is electrical. My scrammy was doin that in forward as well. It turned out that the reverse limiter had actually began to limit forward as well. I had to hold in the override button on the whole way back. I dried the wet muddy machine down and then cleaned all the electrical. This might be the problem. Just a gander but its what happened to mine. Plus mine is a 500.

 

Check the throttle cable. I will make some strange things happen on a Sportsman,

 

The problem you are having sounds like the same problem I had on my 2001 HO and they had to install a new stator that was shorting out after the motor was warmed up.It fixed the problem and runs great now.
Jimmy

 

Also check the exhaust outlet on the muffler.My 425 got stopped up and gave me fits.Also the valves may need to adjusted.And you can do this with a manual and a feeler gauge.

 

An air intake leak will allow the carb to get too much air and lean out above idle causing "no power" and "backfiring". Check and make sure all of the intake hoses are connected to the air box and the air box is sealed properly.