My friend that I ride with has a KFX 400. He recently jet his 4wheeler ( i dont know what size ill hafe to find out) Butt now it wont crank, you can charge the battery, jump it off, or hook another battery up and it wont crank, butt you can push it off and it cranks fine. When it gets warm it cranks with the starter. If anypody can help, please help. Thanks.

 

Some one help, please.

 

weird!!! does it try and crank at all?? id start checking wires.

 

It turns over fine it just wont crank. You push it off it fires right up, when it gets warm it will crank by the starter.

 

Well did the 400 work before he messed with the carb and did he happen to mess with the clutch perch and the wires around there at all...What mods has he done to the quad that he needs to jet and does he know what he is doing...Need more info on this problem exactly.

 

Hes putt a full pipe and a K&N filter. He jetted it to rich the frist time and it crunk fine. He toke it back apart and leaned it down one jet and now it wont start.

 

id put your rich jet back in and see what it does then. check you hoses. i had a hose from my carb to the motor come loose and it wouldnt crank at all. took carb off tightend all the clamps and started right up. you probably need to turn the air/fuel screw anyways. on the bottom of carb by bowl. mines a o5 and i think the new 1's are the same. by the bowl is a little copper piece, i took a little drill and drilled in carefully ,not 2 much ,just a little for it would catch, then pull. the plug should come right out. mixture screw under it.

 

I would check to see if that was clogged up and what size main jet were you using and just make sure all of the vaccuum hoses are reconnected in the right spots on the carb the needle is sitting right in the main jet and check your slow jet also...To me it sounds like either one of the hoses are off or the intake tube or something just give it a closer look and let us know how you make out.