Help with 250F!

[cmaxx]

my dad has a 04 kx250f and it wont idle with teh choke off,and when you rev it up it will shoot flames the whole time.

what could be wrong with it??

[outacontrol]

sounds like its lean, could be kinked fuel line, dirt, etc.

[cmaxx]

well its got a new fuel line,ive cleaned the carb 3 times.have teh air screw at 2 turns out,and have had it in everyspot and ive moved the idle all around.but still nothing.

[Zakradu398]

Spray some ether around the airbox boot to see if its sucking in air it shouldn't be, sounds like an air leak to me.

[cmaxx]

how will i be aboul to tell if its sucking air in or not?

im leaving for the races tomorow morning.so ill mess with it when i get back in teh evening.

[KXRida]

Originally posted by Zakradu398
Spray some ether around the airbox boot to see if its sucking in air it shouldn't be, sounds like an air leak to me.

What he said, sounds like an air leak. When you spray some sort of liquid you will see the air bubble/the liquid disappear. First things first, sounds stupid, but check your air boot to make sure it is COMPLETELY on the carb. The rear shock kinda hides the other side of the boot and it's not hard to only get about 3/4 of the boot on without knowing it. Is this a new onset or what? Was anything changed? Also sounds like a symptom of adding a high flow exhaust. My yzf almost wouldn't run on stock jetting with my carbon pro. If you don't have an air leak, go over your fuel lines again, then I'd resort to jetting. It's lean for sure.

[Zakradu398]

Originally posted by cmaxx
how will i be aboul to tell if its sucking air in or not?

im leaving for the races tomorow morning.so ill mess with it when i get back in teh evening.

If there is a leak the boot will suck in some ether and cause it to reach higher rpms.

Higher rpms= air leak
Same rpms= check somewhere else

Would you happen to be racing at Rnd?