Jetting question

[JonBsbB]

ok i have a UNI filter im running no lid. I have a slip on also. Should i run a stage 2 dyno jet kit?

This is on a 2008 400EX

[honda400ex2003]

you wont need a stage 2 kit. I assume that you have a dyno jet kit? I would run a 146 dj if you have it in your kit. go to 3.5 turns out on the f/a screw and leave the needle alone on the third notch. if you arent running a dj kit let me know and ill give you the keihin setup. Steve

[JonBsbB]

the factory jet was a 146 main

[honda400ex2003]

148 is the stock main, if it had a 146 it was changed. either higher altitude or something else but a 148 is supposed to be in it. usually the high alt jet is a 142 main from what i have read. did you get a dyno jet kit or are you using keihin jets? steve

[JonBsbB]

dyno. yea it was a 148. local shop said to run a 170. if its to rich drop to the next one smaller

[honda400ex2003]

go with a 146 dj first and see how it does. you will also have to switch needles to have it run correctly. leave it on the 3rd clip though. go 3.5 turns out on the f/a screw from lightly seated also. I dont think a 142 will be enough for you. A dealer was recommending a 170 keihin and would have been quite big for a slip on and running no lid, but you can do what you want. I ran a 138 dj with my lid on and would go to a 146 if i took the lid off. steve

[JonBsbB]

The directions recominded the 170 also. ill run it and check the plug and see. Thank you

[honda400ex2003]

good luck with the 190 equivalent size keihin. most guys running 89mm pistons hardly need a jet that but. a 170 is too big for any stock bore motor. you should have saved your money and got the individual jets from the dealer. it is alot more messing around to have to change the needle and such also instead of just doing the jets. steve

[JonBsbB]

not saying your wrong, in just going by the directions from the company that designed the jet kit.

http://www.dynojet.com/pdf/Q107.pdf

[honda400ex2003]

no offense here either but i know what the directions say, i have used dj jets for years. there is a reason i dont use them anymore... the company gives a general idea of what to run with anything and they make sure it is rich enough for them not to get people whining about blowing up from being too lean. a stage 2 on a 400ex would be running all of the things listed with nothing over a 155 dj. that is almost a 170 keihin which is what most 416s run with the supposed stage 2 setup. there is also a reason that it will not run right when you run a 190 in it. it will be too rich, if you notice a difference or not. I ran your exact setup for a long time before i rebuilt my motor. i even ran it with an airbox lid for a long time also. steve