hi. i bought a sportsman 90 about 4 years ago. in about the last year and a half, the sportsman has been having some problems running. it starts up good, but after an hour to hour and a half, the ATV starts sputtering and stalling. it helps if you shake left to right. i think somthing is being clogged. i removed the air filter and found that somthing was broke on the inside. i put on a T tube thing *recommended by my dad* to by-pass the air way. the atv only got worse. i just bought a new air filter and have yet to put it in. i am also putting in new spark plugs. what i am wondering is:
could this maybe be the automatic choke?
could this be the carb is clogging?
if this has happened to anyone or someone you know, please help me out. i really wanna ride before i get downpoors of snow!
-wuderkid14

 

We've not run into any problems you've mentioned, sorry the only problem we've had is it stalled on us and would not start back up, we still had spark, but it would not turn over, we finally replaced the spark plug and it fired right up..


you can go to the polaris web page and download a owners and parts manual for them...

 

i wish i could help ya more but what do you mean tubing to bypass you dident bypass the air filter did you?? i think its a 2 stroke and if you bypass the air filter your going to run way to lean...put the new filter in and see how it goes..you might want to try and open your air screw a 1/4 turn also "on your carb"
mine hase given me fits on the 250 kind of what your describeing in different air temps...