main jet styles for ex

[2001400exrider]

wat is the name of the style of the Main jett for a 400ex ?!?! how do u specify wat kind of jet u need ?

[cals400ex]

keihin hex mainjets (13 series)

[2001400exrider]

will it say 13 series on the jet? because i called my dealer looking for some main jets 180-200 and they said i will have to take my carb off and bring in the jet and possible the whole carb ?! i just want SOME JETS!!!

[400exredrider]

just tell him you want kehin hex headed jets... he should know what that is,,, or if you tell him what the carb is from he should know too,,,, i cant believe some of these dealerships these days. they are pretty dumb

[400exredrider]

and no they wont say 13 series,,, the only other seires from kehin is like 12 or 14 i forget which way but they are short jets,, they will have the kehin K stamped on them and have the number on it

[zephead400ex]

Good lord, what do you need that big of jets for?:eek2:

[2001400exrider]

Full HMF system, and uni filter. HMF site says 200 but i went on the HMF forums and tech guy said 180 is about rite.

[kilabeez0]

your out of your mind if you put a 200 on there!:huh

and is that your wish list or do you have all that stuff and dont know what kind of jet you have?

~~i paid $315 shipped for my brand new HMF full exhaust, HMF doesn't even list it as $500.

[2001400exrider]

"wish list" lol.. i only got renthals, HMF full system and uni so far..




ps....im CANADIAN...my hmf came to 600$ shiped plus 127$ brokerage fee from UPS so came to 727$ :rolleyes:

[2001400exrider]

what jet is everyone using for their HMF full system !! i cannot get a clean anserw with only one person replying

[400exredrider]

where did you find a full HMF for 315 shipped?

[HondaR]

you need to tell them you want a keihin 13 series main and 21series pilot im sure your going to change that to right? it doesn't say it on the jet but it is the type of jet your ordering

[cals400ex]

Originally posted by HondaR
you need to tell them you want a keihin 13 series main and 21series pilot im sure your going to change that to right? it doesn't say it on the jet but it is the type of jet your ordering


this is correct. the dealer just doesn't know what they are talking about. i replied to you in another thread on what I jet at. the jet won't say keihin or it won't say 13 series
it should have a K on it (for keihin). the K does kind of look like a star though. also, it will have the jet size on it. nothing else.

[zephead400ex]

Jetting depends on temperature, elevation, etc. However, a good starting point on jetting would be a 42 pilot, 152-155 main jet. 180 main seems way too big.

[HondaR]

i would go with a 160 -165 and 40-42 pilot but like zephead400ex said it has alot to do where you live

[2001400exrider]

I live in Ontario Canada, does that help ne one ?! can anyone find the elvation for me and tell me wat jets would be suitable, so far i guess ill start at 160 main and throw in a 40-42 pilot as well. But the pilot jet will just help me start easier correct? becuz pilot is for low low rpms... ?

[zephead400ex]

You are correct. The pilot jet helps with starting and up to 1/4 throttle. If you do decide to go bigger on the pilot, go with a 42.

[2001400exrider]

thx. will do:D