Just bought a new 2008 400 auto 4x4 put a few miles on it last november and some this winter, but recently took it to my camp and started putting a few more on it when I noticed that while riding it would bog down and want to stall i would have to feather the throttle to keep it running. it would act up for a few minutes and then it would be ok for a while only to act up again this went on all weekend and I am not sure what the issue would be and would like some information on what this might be. I do notice that at times some fuel will spray out of the breather tubes that are located under the speedo it also seems to do it more when it is hot.
Ant help would be apprciated

 

With it running and it starts doing this, can you turn on your lights/accessories and it clear up? If so, with the engine running, check the voltage reading at the battery. if you are greater that 15.5 volts (I think that is the magic number) then you have a bad rectifier. mine did this and I checked everything on it/in it before i found the problem. Too much volts will cause it to hesitate and stumble.

 

So will a gummed up carb. Run a can of SEAFOAM thru it and see if that helps.

my .02¢

 

No because we did a night ride and it still acted up. I am thinking since I bought it last november 2009 new and it was a floor model it has something to do with it sitting so long. It is still under warranty how hard is it to pull the carb off and go through it or should I just take it to the dealer? Your guys thoughts?

 

As long as it is under warranty, take it to your dealer.
You paid for that warranty when you purchased the quad, and if you do any modifications yourself, you give the manufacturer a easy out from fixing the problem--they will claim you broke it.

 

Something in the gas? Maybe?

 

I have 2008 700 EFI and it would do it as well. Took to dealer 7 times and it turn out to be the coil. Once it was replaced I have not had any issue since. So if machine is under warranty I would certainly have the dealer look after it.

 

Thanks all for your help sea foam is where I will start then If I have to I will trailer it back and take to the dealer. Thanks again