my 2002 sportsman 500 4x4 has a hard time starting,once i get it started it idles good. the problem comes when i give it gas, it starts sputtering and backfiring and has no power, but i can put it in gear foward and reverse and it will move just at 1/4 throttle anymore than 1/4 throttle it bogs bad and does not rev up. it has a new stator, pulser,cdi i replaced all that because i bought it and it had bad spark so i replaced all that and know i have spark and another problem, could it be fuel related,timing ? any help would be great.thanx

 

Remove rocker cover and check if center cam lobe(exhaust) worn or ground down,IF eliptical like the intake lobes,then check valve clearance(.006 intake and exhaust),if runs the same check carb for stopped up jets or water contamination. Stator plate has timing mark that lines up with mark on case.

 

On the 500 do you have a rubber boot between the carp and head like the 02 700 dose.sounds like it got a spit in it.

 

i will check right now,thanx

 

<div class="FTQUOTE"><begin quote>Originally posted by: old polaris tech

Remove rocker cover and check if center cam lobe(exhaust) worn or ground down,IF eliptical like the intake lobes,then check valve clearance(.006 intake and exhaust),if runs the same check carb for stopped up jets or water contamination. Stator plate has timing mark that lines up with mark on case.</end quote></div>

There you have it

 

thanx for al the help, guys but stillthe same. im so disapointed. i bought this quad and the guy only told me it needed cdi box,so i bought it, $800 for an 02 sportsman 500 4x4 was awsome if thats all that was wrong with it. well know, new stator,new pulser,new cdi just tio find out this problem. i dont get it. i even have the clymer book, and i cant fix it. "this sucks cause when it idles it sounds mean".

 

its going to be your cam. check it out closely. you can tell if the lobe is missing.

 

i dont want to sound dumb, but here it goes. were is the rocker cover to check cam lobe and how do i check it ? turn the engine over till i see it? sorry for the dumb questions but this is my first polaris.thanx

 

another thing the rubber boot that bill35 mentioned above, looks lack it has a crack in it along the crease where mounting screw hole. but it looks to be just hairline and not all the way through, and while running i revved it a little and sprayed starting fluid on the crack and nothing. if it was brocken all the way through it would have sucked in starting fluid and revved up or died or something but it done nothing so im not sure if boot is problem.

 

im getting frustrated, if i cant get this beast going. i will probably get mad at it and part it. id hate to it is a nice machine.