i have an 03 kfx 400 and it starts up cold fine and idles good but after 5 mins of riding it bogs out real bad when i give it gas but it still idles, then if i stall it it won't start until it cools. the exhaust pipe turns glowing red like its being heated with a torch. any ideas ?

 

sounds like its lean, is it backfiring? somebody check me, if you pipe glows is that lean or is it rich and the extra gas is burning after it leaves the motor.

 

yes it does backfire a little

 

I have an 03 Z400 and i had a simialar problem, just my exhaust pipe didnt glow red hot. It just bogged out and stalled like yours. It turned out the choke was stuck on.

 

Does it backfire or pop? There is a HUGE difference. Popping just...pops. Backfiring is a very loud "bang".

Check to see if your choke is stuck on, sometimes with the system they have the cables freeze up.

 

when i first start it i put the choke on until it warms up, when i shut it off you here the change in the engine so i know its not the choke and i guess you would say it pops, not a backfire

 

Does it run better with the choke on or off.If it runs better with it on it needs more fuel (jetted).The header pipe glowing red means its running lean have you added an air filter or pipe ect.If so it needs jetted or the air fuel mixture needs adjusted.