My dad baught a brand new sportsman 400 4x4 and it runs great, really like it. One day i went up this pretty steep hill in 4x4 i think and it climbed great but when i would give it gas prob over 1/2 sometimes even 1/4 it would bog and sputter and not climb, which kinda scared me but when i would keep the throttle just slightly on it would run fine. Now i dont think its an airfilter thing or anything becuase it runs fine any other time and my uncles quad (exact same one baught same time, but has less miles) does it up hills too.

I think it is too rich from factory. Does this sound right to you guys? Becuase i know they jet them rich form factory and my unlces does it too.
Is this my problem, just drop some sizes on the main?

 

If you are going up a really steep hill you could be running into a problem of fuel delivery. The system is gravity fed, and it may not be able to keep the bowl full up the hill and in turn it would run like it is starving. Just a thought, but it could be something else.

 

If you do a search on all the sites you will find that the 400 Sportsman was jetted way too rich from the factory. They come with a 172.5 main and depending where you live some guys have jetted down to a 162.5........

 

NBsportsman is 100% correct. Polaris inexplicably changed from a 167.5 to a 172.5 post 2003. Go back to at least a 167.5, or leaner - it'll depend on your riding altitude.

 

I had the exact same problem, on any sort of incline that put the engine under a load. I took the machine back to the dealer, since it was still under warranty, they rejetted to a leaner jet and it runs great now.

 

Thanks for the info, guys!
I've got an 04.5 400 Sportsmans thats been bogging on me since it was new. Had it back to the dealer twice and they couldn't fine the problem. It just about did me in on a hill once and boggs under a load about 1 in 10 times. Rejetting seams the the way to go!

 

CmdrBen, did you rejett your 400 ?
If so, what size did you go to?
I've put a request into Polaris to see if they would help, the last time I had it into the dealer, they charged me 70 bucks!
Thanks.....

 

Bendix - I did. I got the Dynojet kit. I ride anywhere from 4000 to 10,000 feet so I needed some flexibility.

 

Forgot to add that there was a Polaris tech bulletin out on the carb jetting. Dealers ~should~ know about it.

 

Thanks guys, it does definately sound like they are too rich from factory. Were going to leave it now becuase we will hopefully not need to rejet it for the winter now and then just rejet next summer.

Oh another thing. My uncle took his in for this problem and they removed two shims from one of the cluctches and they said the problem was the belt was slipping. My uncle said it fixed the problem but i think it maybe just helped by changing the gearing slightly so that its not under as much load going up hills therefore making the rich jetting problem not stand out.

Thanks for the info!