carb change over need help

[465dragbike]

I have 2000 400ex and it has a stock carb right now. I'm boring it to a 465 and need a different carb. So I'm looking at getting a crf 450 or a 450r 06+ carb. Which would be best and how do I get them to fit on my ex?

[Blodg]

There are hundreds of posts on how to adapt and fit the carbs for a 400ex, use the search or go to the frequently asked questions in the forum. There is no need for any of us to try to explain it here.

I have both an FCR carb on one quad (which is what you are referring to above) and an '04-05 450R carb on my other quad and they are both great upgrades. The '04-05 450R carb is easier to tune/jet however and cheaper.

[atvrider13]

the 06 and up trx450r carb doesnt fit very good on a 400ex. An fcr from a yfz450 or crf may fit better

[CJM]

Might want to try a 04-07 FCR off a 450r dirtbike, thats what alot of guys use for the 04-05 450r quad conversions. I went with an 04-05 450r carb on my 400ex and I liked it alot, smooth power delivery and good power. FCR are nice but super snappy powerwise imho.

[JOHNDOE83]

the 06 and up trx450r carb doesnt fit very good on a 400ex. An fcr from a yfz450 or crf may fit better

I got the 05 450r carb to fit right on my 400ex with hardly any modifying, I removed the choke lever, blocked the hotstart with RTV, changed the breather hose position and bought a 2in $4 rubber grommet from lowes and it went right on with no issues.

You dont need a $45 adapter and you dont need to sand anything down.

The FCR is only snappier because of the flat slide, other then that it doesnt offer any HP change, the 450r carb is a larger bore carb and offers the best peak HP and is whats really needed for a 465 build.

Just my opinion.

[465dragbike]

Thanks everyone!! I'm new to this kinda stuff

[400exshop]

Thanks everyone!! I'm new to this kinda stuff

I my self do not like the 04-05 450 carb cuz it just a bigger 400 carb same set up its a vac carb the yfz crf carb is better for a all around carb quicker throttle response pulls better out of the corners and if you want to get crazy with your motor like a 460 aka the 465 stroker motor port the head better exhaust you can have that carb bored to a 42.4 or 43mm and have a bad *** bike so its all in what you want to do. but I my self would not build anything past a 426 with out a crf carb and a good ported head cuz its a waste of time and money and so much untouched power left in the bike. but that's just my opinion. good luck