My bike is running rough..I cleaned the carb, new spark plugs but it still back fire and sputters

 

Hi, my 2006 400 big bear was doing the same as what you are talking about. I had gotten water in my fuel tank - so, I drained the gas, added fresh gas along with a bottle of HEET GAS TREATMENT and did the same things you did and that has fixed my problems!
good luck,
earlthepearl

 

don't know if its like the old 350's, but if it is, drian the bottom of the carb bowl 2 and that will help, I had hell for about 2 weeks one time until I finally got all the water out, of course I had sunk the damn thing so what do ya expect

 

My Bigbear does the same thing. I dont ride it much but it shoots sparks and it backfires alot. I Suggest you take it to your dealer and get the valves adjusted, also see if it has a leak or somethin in the exhaust were its getting more air then it should. I let mine go for so long it broke some of the baffles in my muffler. So make sure you fix it right away.