Quite a difference! Early models had the pulling power in the hubs(coil,armature plate,roll cage assembly, and four bearings in each hub) Centralized awd drive systems were contained in the front gear case. OPT

 

Mines an early model then. Build date is 5/13/03

 

My Polaris 500 misfires at low throttle but seems to run fine at high throttle. I don't want to drive fast all the time. At low throttle it misfires and dies. I replaced the plug, new air filter and cleaned out the carb but did not replace any carb parts. Any suggestions?

 

Make sure you have only 1/8" slack at the throttle lever or it's possible the etc contacts can touch causing problems. Adjuster is under the rubber sleeve on the throttle cable.One of the things most people overlook.Plus just my on this one. Any time I removed a carb,it got rebuilt. Not worth the trouble of having to go back in for any missed spots or worn parts.Carb may or may not be the source of your miss,but you can at least you can rule the carb out when you rebuild it.Plus you can pull the fuel line from the carb and crank the engine over.Should have a steady stream of fuel from the line. This is to rule out any fuel supply problem from the pump,stopped up fuel filter. If none of this helps,then could be an electrical problem and this is where a manual would come in. Has a section on electrical miss along with general checkouts.
Worth the 5 bucks if you don't have one already.2004 Polaris Sportsman 500 Service Manual PDF Downloadhttp://www.ebay.com/itm/Polaris-Sportsman-500-2003-2004-2005-Carb-Carburetor-Kit-/261420203486?pt=Motors_ATV_Parts_Accessories&hash=item3cdddbbdde&vxp=mtr