backfiring when let of throttle

[uspatriot]

2000 400ex
stock main jet
42 pilot
white bros slip on
K&N filter lid still on


I installed he 42 pilot trying to get rid of the backfiring when letting off the throttle. This helped a little bit but it still backfires. What else can i do?

[250x_kyle]

your two lean. play with the fule mixture screw or possibly go up a main jet size.

[BlasterEaten250]

I would go up to a 152 or 155 main jet

[uspatriot]

Ok thanks ill try a larger main and see what happens

[Sanddraging28]

make sure you dont have an exhaust leak...look for carbon build up on the motor end of the head pipe

[Eviltanker]

Adjust your needle also

[uspatriot]

How do u get to the needle on this carb, its not like other carbs ive worked on where u just unscrew the throttle cable at the top and the needle sides out?

[Sanddraging28]

remove the top plate, take the two screws out of the slide. the needle in under there

[uspatriot]

THanks

[the Z Man]

Install new donuts, also recheck your slip on for leaks..