400ex carb on 300ex

[fox17]

how hard is it to put a 400ex carb on a 300ex and what jetting and other mods are required.

[bwamos]

Most will use an atc350x air boot for a better fitup.

Jetting, depends on what mods you have done to your ATV.

I don't know that I'd bother with it on a bone stock motor.. but if you do, start with the 400ex stock jetting and work from there.