06 400ex runs like crap

[NRTHBUSH]

ok ive been having a rough time geting 400 to run right..... its basicly running like junk and changing the jetting doesn't seem to do anything.... i get seriouse throttle blip and and basicly very little power. my dyno jet needle clip broke so i put the stocker back in... its not adjustable .all i have is a fmf power core slip on and my air box lid taken off. should i go back to stock jeting..... and how offten do you change the seal on the carb. mine seems to not fit right . so im buying a new one...... just want it to run properly .its a 4 to 6 week wate at the shop. help.

[GlowBoy]

With all the jetting changes you have done, chances are the plug is fouled out. Change that and see what happens.

[NRTHBUSH]

i have put in like 8 differnt spark plugs now.
this was brand new spark plug. i put in

[GlowBoy]

Vacuum leak maybe, **** I'm stumped.

[NRTHBUSH]

do u know the stock jetting....... ? gona try n lean it out a bit to much then put my air box lid on to richen it if needed.

[Eviltanker]

38 pilot and I believe 142 main.

[kolby2004]

The stock jets for a 400ex is 148 main and 38 pilot

[Eviltanker]

Thank you

[kcliff]

Bush try the bottom screw on your carb where you let gas out, I had a bad time with mine because of it switched needles and exhaust (i was going to anyway) an it wouldnt run right then i made ome calls and someone suggested my carb had an air pocket or something like that, any way i turned the screw out waited till gas came out, you might need to push the throttle a little and see if that works

[Exrider434]

try gas from a different place.... i live close to the indian reservation in ny and the gas there is REALLY cheap sometimes 1.00 less.....but anyways i found out the hard way why its so cheap, well there was water in the gas...rotted out the gas tank in my dads truck and my old 300ex...needless to say we never buy gas there anymore

[Sparky_20]

x2 on the gas. Drain the tank and carb and see what happens.