Hey guys I've read your posts on the 400ex being lean from the factory. I live in ohio. What are some of the tell tale signs. I've been riding it for a while now. There is no hesitation but the throttle response doesn't seem to be what it used to be. I also noticed that the engine is running pretty hot and the exhaust smells a little chrispy. Any help is apperciated.

 

I live in ohio also i notice that even before i added my pipe and K&N airfilet with vent holes in air box
now it real bad. now that i have been told by alot of people on the forums here what jet i need to goto im jetting tomorrow before I do something to my engine............also where in ohio do you ride im look for more places to goto so far i have been to obets,honda hills,summorset,wayne

 

Hey man did you do anything about the lean condition before adding the pipe and filter. If so let me know what you did. I'm gonna leave mine stock for now until execpt for chassis mods.

 

Hey lucis, where is honda hills and summerset. I live up in the northeast part of the state. I ride at my house and my buddies. we ride at a place call hana hills and want to take an excursion up to a place call silica sand. i hear that there are sand dunes and some trails. If its worth going i'll let you know

 

i was told to jet to between a 150 to 155 main and up one size with pilot but on pilot they said i dont have to
so im going to go with the 150 if you know of M.J that owns M.J usa he has a 400ex and said there no reason to go past a 150 main and not to go up on the pilot he change his to a 150 when it was stock and keep it at 150 with all the mod he has done.

honda hills is a mx track off ill get the way to it and post
summor set is really perry county forest park

 

so what your saying is just take the main up one jet size and leave the pilot alone okay got it. Now what about the needle, stock position? Hey by the way do you race? thanks for the info

 

(LUCIS) AS YOU CAN SEE I TO LIVE IN OHIO AND DO
NOT AGREE WITH M.J. USA AT ALL. WITH A PIPE, K/N, AND AIR BOX VENTS YOU ARE RELEASEING MORE AIR AND TAKING IN MORE AIR. YOU NEED TO GIVE IT MORE GAS TO. PUT IN A 155 MAIN JET AND THAT WILL PROBALY BE PERFECT.

AND AS TO M.J. USA SAYING THAT YOU DO NOT HAVE TO GO BIGGER EVEN WITH MORE MOTOR MODS.
I JUST HAD MOTOR WORK DONE AND WENT FROM A 146 JET TO A 160 JET (DYNO JET KIT).

99 426EX, 11 TO 1 COMPRESION, PORT JOB, REV BOX, K/N, DYNO JET KIT, 6 AIR BOX VENTS, IDS-2 SUPER TRAPP PIPE.

 

Hey 426ex, what do you say about the factory jetting being lean, I just raised the needle 1 notch and took the slack out of the throttle cable. I agree though you have to go bigger the more air you let in. IF it wasn't lean from the factory, it sure is now with a k&n filter and pipe.

 

Hey 426ex, what do you say about the factory jetting being lean, I just raised the needle 1 notch and took the slack out of the throttle cable. I agree though you have to go bigger the more air you let in. IF it wasn't lean from the factory, it sure is now with a k&n filter and pipe.

 

If you are wondering about the 400EX lean condition when stock, look no further than page 143 of your owners manual ("Source of Emissions" section)....

Personally, I don't too much care for the EPA jetting my bike.....