need help jetting my buddies 400

[TheLadiesMan]

im not good at jetting so ive turned to you guys. please give me a hand. thanks


03 ltz400
all stock except for a k&n filter (still has lid on) and a LRD full exhaust.

right now he says it runs great down low but when you get in higher rpms it pops and cuts in and out

when i pulled the plug it has some carbon build up on it but it isn't wet.

all i know about his carb jetting is its stock except for a 155 main. elevation is 1020 ft.

thanks for any help. i really appreciate it.

Lance

[TheLadiesMan]

ANYONE???

[drzoo2]

Keep dropping your main until it stops popping. Take the lid off were you are now and it will run strong.

If taking the lid off makes it better your rich.

z

[cataway]

Originally posted by TheLadiesMan
im not good at jetting so ive turned to you guys. please give me a hand. thanks


03 ltz400
all stock except for a k&n filter (still has lid on) and a LRD full exhaust.

right now he says it runs great down low but when you get in higher rpms it pops and cuts in and out

when i pulled the plug it has some carbon build up on it but it isn't wet.

all i know about his carb jetting is its stock except for a 155 main. elevation is 1020 ft.

thanks for any help. i really appreciate it.

Lance

what kind of jets are being used ?
as well the pilot jet my have to be changed to a #25 and the fuel screw will have to be adjusted.
i suspect the porcelain electrode on the spark plug is white or at least not a mince tanbrown color. is that right ?
honstly if any one is going to run with the lid on why a pipe is ever instaled