i recently bought a 2000 big bear 400 2x4,the guy ibought it from said it sat for a couple of years with minimal use. it is like new with very low miles.even original tires almost 100%. I noticed when starting it the idle would go up and down on its own,would run fine when using but bad idle. i rebuilt the card cleaning it out very well , it ngot better but when starting cold it has to sit on half choke for about ten minutes before you can move it, or it will miss and stall. even sometimes when in use it will give a pssst miss,but if you turn the choke on it stops. another thing is if you go past half with the choke it kills the motor, it will only start on half choke. is it possible the choke needs adjust, how do you do this?

 

Did you remove and clean out the pilot jet screw? I had the same trouble out of mine and doing that cleared it right up.

 

when i rebuilt the carb all the jets were replaced with new

 

i hear a lot about valve adjustment,could this be the problem?

 

I have a 2000 Big Bear 4x4. I'm having issues with mine as well. I had the carb rebuilt. It runs great as long as I don't give it full throttle. If I do it pops and sputters and loses power. I haven't had the valves adjusted in a while. Maybe I should take it in and have them adjusted.

 

thats what im thinking of doing with mine,any idea what that costs? do you think its possible thats why mine has to warm up before using. but when warmed up it runs good except the other day my son said he had it opened up for a while and it started missing , so he chocked it and it cleared up. its driving me nuts

 

I don't know if adjusting the valves will fix my problem on not. I'm just going to try to eliminate everything I can. Plus I haven't had it done it a while. I think I'm going to try to find a shop manual and learn to do it myself.

 

Before I had the carb rebuilt I couldn't turn the choke on all the way or it wouldn't start. I could only choke it halfway. Now I can choke it all the way and it runs a lot better (while choked). I had a problem with the plunger. They honed out the hole where the plunger go's and now it slides in and out nice. My choke problem didn't effect it once it was warm though.