My 98 Sportsman 500 is very hard to steer and is pulling to one side. I have had it checked out and it didnt help anything. I thought one hub maybe sticking and I have checked and adusted air pressure and toe end. One Arm has a knick on the bottom but dont seem to be bent. Does anyone else have any ideas?

 

Sounds like you might have a brake locking up.

 

I agree on a brake(s) being your problem. Time to check or change those front pads.

 

It also could be a 4wd hub locking up when it isn't supposed to.

Try changing hub fluid first, if that doesn't work, you may have to disassemble the hub.
The first thing to check would be if the spring that goes around the rollers is broken.
Next would be to be sure the bearings are all good.
A bent axle can also cause erratic lock-up, something to look at if the quad was in a wreck shortly before this started happening.

Farmr