check filter is running right direction. then maybe its in throttle linkage.some times my adjustment lock bolt shakes loose,up on handlebar

 

the filter can only go on one way, but i'm going to pick a new one up today (hopefully thats the cure)

 

CHECK THE SPARK PLUG WIRE - my brothers had the same problems - the wire was cracked not the rubber though a few inches from the plug

 

I think he was talking about the fuel filter

 

After checking the easy stuff, Check the cam exchaust lope. They are known to wear down. It sounds just like my neighbor's and that what was wrong with his. Yes, it can happen all at once. Do a search for sportmans rough running and cam and you'll find that yours is acting just like there's did and they found the cam warn down.

 

changed the air filter today, and it still does the same thing. as for the fuel filter isn't it in the tank? what about the fuel pump? would that cause the problem

 

Is this a four stroke 400? Certainly could be the cam. But I thought they had cured the cam issue. Pop the valve cover off and take a peek.

 

i dont think they made a 2 stroke 400 sportsman in 02'

 

its a 400 4 stroke with about 210 hours on it. how does a guy go about checking the cam, i dont know too much about small engines (but i get buy). do i look through the top cover or the side cover on the right side?? before i start ripping apart the motor i'm going to check the plug wire for cracks and wear.

 

checked out the spark plug wire and that looks good, the vent lines are clear. i run it today until it got warm then a gave it full throttle for about 10 to 15 seconds, then i pulled the plug and it was a little black (it was a brand new one a couple days ago) i'm thinking that it maybe a bigger problem than i expected, i might have to get a new cam for it