we have a 2005 kfx400 it will only start it we pull start it it back fires pops craps etc thens starts up and runs super untill you let off the throttle then it dies and will not start unless you pull it. its in time changed the spark plug changed the fuel checked the spark has a 440 bb kit with plenty of compression what in the workd going on with it

 

Try adjusting your idle screw,check the stator

 

neither one of these are my problem. when it trys to start some times it kicks back like it is out of time.

 

when trying to start it does it click?It could be your starter clutch not wanting to engage.

 

starter is working great its a carburetor issue im thinking since it will not idel you can not let get lower then like 2500 rpms this is the first model for the tps on the carb

 

pulled my carburetor apart did not find anything but fuel behind my air cut off diaphram im thinking thats becuase of it back firing and puking gas in there. it has 165 compression its in time it fires when it should but it will only run at 1/4 or more throttle and we have to pull start it for that. it will suck you hand in the intake of the head with the carb off. im leaning to the tps anyone had problems with this?

 

update. when i checked for spark i did not check for constant spark it only sprks one time thats it everytime i hit the start button it sparks once i can hit it let off hit it again it sparks one time. is it the stator or cdi?

 

my tps gave me a problem not too long ago but it did stay running. it just wouldnt rev up. it would sputter and backfire when throttle was applied. i took it off an srayed some pb blaster cuz it didnt spin left or right good. put it on an had same problem.....so i banged it with screw driver an it worked good ever since. it stopped working right becasue i rev limitered it too much.my advice is to tap it a bit.

 

it was my pick up coil. replaced it runs like it never has super strong must of been weak for a while. anyone want to buy a nice tricked out 05 kfx400?

 

did you put it on prime i had that problem