Carb swap 300ex to???

[4x4_war]

Wondering if i got a diff carb for a 300ex, and put on a 400 ex/ r carb on it would i notice any difference or will it even work?

[fmftrx300ex]

iv done alota reserch on upgrading 300ex's because i also have one and am unsatisfied with its power and suspension you can fit a 400ex carb in with almost no modifications its alil tighter in the rubber boots and may need to be rejetted unless you have an exhaust and airfilter and other mods you may be able to avoid the rejetting if you have a filter and pipe, need anything else pm or just reply

[rooster300ex]

u really think stock 400ex jets would work. if thats the case i might pick up a 400ex carb to add to my intake mods.

[honda400ex2003]

heres a bit of info on some carbs. Check out the 300 section and see what else they have to say about some of the other carbs around.
http://exriders.com/vbb/showthread.php?s=&threadid=411983

steve

[4x4_war]

ya. i have a k&n airfilter, and an fmf megamax 2. so do you know of anything else i can do that's fairly cheap fmftrx300ex? and where can i get an ex 400 carb cheaply, used?i have tried some junkyards online, but i have no responses from them, i wat to just go to the junkyard, and take it off, and whatever else i need and pay them in cash. not this internet crap :) lol, but is there any where near watertown wisconsin that you know of?

[fmftrx300ex]

altho u asked to avoid the internet ebay is proably ur best bet you can pic one up for around 50 bucks on there and yes i do think you might be able to get away with stock jets< a stock 400ex has a 148 im pretty sure the 300ex's stock is a 132 so u may need to jet down alil also depending on air temp and elevation magicracing.com sells individul jets for about 6 bucks other modds i recomend 14tooth front sproket from rockmountainatv.com tusk makes them they cost about 10 bucks and it will make ur gears pull longer because it wil gear you up i dont recomend it if you like putting around at like 10mph at 1200 rpm thats all i can think of as far as cheap engine work

[4x4_war]

ok. thanks for the info n advice. i'll be working on it over winter, so i'll c what i can do. but i will def b putting on the 400 carb and the sprocket. i might be porting the head too. so i'll let you know.

[fmftrx300ex]

I do deffinitly recomend porting as the 300ex does have some pretty restricted ports but if you plan on doing it your self I sugust geting very acostomed to the tools you gunna use and practice on something less expensize like a lawnmower, also bigger isn't always better so read up ok port design it's a big help.