help with big bore jetting

[trxPOWER]

hey guys im looking for some advice on how to jet my quad. Here are the mods: 440 big bore kit, slip on, and stage 2 hotcam. the air box lid will be staying on. Thanks for any help!

[honda400ex2003]

190 main, 3rd notch on the needle, 42 pilot 2.5 turns out on the f/a

do a plug chop for each part and see how it does.

you can tune the f/a screw accordingly using the proper method also

i would say you will be a bit rich and will probably end up at around a 180-182 main.

read through this for each of the discussed items above.
http://www.exriders.com/vbb/showthread.php?s=&threadid=445695&highlight=jetting+placement


steve

[trxPOWER]

thanks for the advice! and im wondering dose the bigger bore size make for a bigger main jet? i am going to be running with the airbox lid on, is my main still going to be that big?

[honda400ex2003]

usually bigger bore means bigger jets. even with the air box on i feel you will be up around 180 as suggested before. its better to start rich than to lean. then you can work your way down a couple of sizes.

i just gave a suggestion to get you close.

steve

[trxPOWER]

thanks a bunch dude i really appriciate it, i had no idea where to start with jetting.

[honda400ex2003]

good luck with it. remember that will just get you closer to where you need to be. fine tuning is up to you. steve

[JOHNDOE83]

Do some fine tunning, my 440ex needs a 220 main to run right.

Do some plug chops, or just jet higher till it sputters then back off about 5 jet sizes.

190 will be a good start and probally right around where you wanna be like steve said.