jetting ?

[07honda400ex]

Ok I just bought a hmf slip on for my 07 ex what size main jet should I use? I ordered a 152 and a 155 and a 40 slow jet do you think that is about right? I dont have any mods other than the air box lid having some 1 inch air holes drilled in it.

[honda400ex2003]

you should be close with the two that you bought, try the 155 first, do some plug chops, see how the plug is. if it is black put the other one in and try it. pick the better one out of the two. if either one are brown color you are good for the main then you can do the pilot and the needle. needle first then you can do the pilot. do the same for each, you can use the same plug but make sure you can tell the difference each time. if it is too black then use a new one for the needle and the pilot and such. steve

[honda400ex2003]

i guess you could use an O2 sensor to monitor the mixture, that could get a bit expensive though. steve

[clemsonteg]

Originally posted by honda400ex2003
i guess you could use an O2 sensor to monitor the mixture, that could get a bit expensive though. steve

It depends on what you consider expensive. You can get wideband O2 kits with a gauge for as little as $230 (LC-1 from Innovate and a digital gauge)

[clemsonteg]

You can also go somewhere like 14point7.com and get kits to build your own wideband O2 or even buy and assembled one from them for really cheap. I know some people over from homemadeturbo.com (when I used to be into imports) that use them and are happy with them. For those guys its all about budget so it might would be a good option for a quad.

http://14point7.com/Widebands/NAW_7S/NAW_7S.htm