400ex Jetting On My Own: Advice needed

[atvhonda-rider]

Ok... i dont have the money.... correction i dont want to spend the money to have a local shop jet my carb, i know all but how to jet carbs!! I need any advice on the fastest way to get my carb out, and install a new main jet with my new exhaust... thanks!

[GPracer2500]

No need to remove or even rotate the carb for main jet changes. On the bottom of the float bowl there is a cap that can be removed with a 17mm wrench or small crecent wrench. Remove that cap (after turning the gas off!) to gain access to the main jet. Using a small mirror to look up in there might help you orient yourself the first time. You'll see the main jet in there staring down at you. Use a 6mm (1/4" is pretty close too if that's all you've got) socket to remove/install the jet. If memory serves, a deep socket on a 1/4 drive ratched is just about the perfect thing. Don't tighten the jet too much. Just snugging it up is all it needs.

[Honda#4]

Nah i wouldnt use a deep socket cus he might put the socket on to far and screw out his entire main jet assembly. A reglar socket is fine.

[GPracer2500]

Originally posted by Honda#4
Nah i wouldnt use a deep socket cus he might put the socket on to far and screw out his entire main jet assembly. A reglar socket is fine.

The part the main jet screws into is larger than the jet. I don't see how it's possible to put a 6mm socket on too far. The end of the socket will just bump into the emulsion tube and go no further.

The particular deep socket I use won't let the jet any deeper into the socket than a regular socket anyway. Only the thinner bolt part of a nut/bolt combination can go all the way through it. Not all deep sockets are like that, but I don't think it would matter either way.

I suggested a deep socket just to make things "handy". A regular socket on an extension can work just as well if there's clearance. I've always found a regular socket by itself to be too short to manipulate easily--to much of it gets swallowed into the bowl. In my jet box I keep a deep socket, a regular socket, a swivel head socket, and a socket extension. Between those tools I've always had some combination that was "just right" for getting mains out of various carbs.

Whatever socket type works for each person is good enough for me! :)

Emulsion tubes WILL sometimes come out with the jet. This is kind of a pain since you've got to remove the bowl to re-install it. This can happen from frequent overtightening of the jet into the emulsion tube. Breaking an overtightened main jet loose will eventually bring the emulsion tube out with it.

[Honda#4]

Yea I guess whatever works go for it, I just used a small rachet and socket and that worked perfect for me but the whole thing came out anyway so i had to take my carb off and put the whole thing back on.

[atvhonda-rider]

ok, well im ok just replacing the main jet right? i'm all stock but the HMF exhaust. i didnt think i needed to work voer the needle or anything else?

[GPracer2500]

It may not be perfect but you can certainly get away with only changing the main.

[atvhonda-rider]

so im just robbing myself of extra ponnies when i dont do everything? doesnt hurt naything to do just main right? i can alwasy come back and dial in everything else?