Finishing up my build

[Bill Martin]

Hey guy's I'm new to this forum and it looks like there are a few of you that have been running the 400ex for awhile so I have a few questions you could chime in on.

I have a 07 ex that has had:
Head ported & polished
Board to a 416
12-1 piston
Stage 2 hot cam
W/B MX4 slip on pipe
Chock plate and bar out of the carb.
Over sized aluminum oil tank.

That made a fairly good increase in HP's after break in.

I am going to do the head pipe and carb next.

The pipe will be made by a professional so it will be right.

To my questions:

What brand and type of carb to go with.

What's the cheapest?

What's the best?

What do you use and why?

Were you satisfied?


Thanks guy's you have a great site here and I'm glad I found it.


PS What fuel should I run?

I've been useing U-4.2: Yes-No?

[rob_990]

id use the 450r carb cause you can find them for pretty cheap

[bergoff]

save your money and just grind the welds on the head pipe. http://www.exriders.com/vbb/showthread.php?s=&threadid=334885&highlight=grind+welds+header

there are always a lot of 450r carbs on ebay.

[dariusld]

Originally posted by bergoff
save your money and just grind the welds on the head pipe. http://www.exriders.com/vbb/showthread.php?s=&threadid=334885&highlight=grind+welds+header



This is good advice for a stock machine, but not a heavy breather.

[Bill Martin]

Originally posted by bergoff
save your money and just grind the welds on the head pipe. http://www.exriders.com/vbb/showthread.php?s=&threadid=334885&highlight=grind+welds+header

there are always a lot of 450r carbs on ebay.

Never thought of that: makes since though.
I gotta believe that on something that only has 35 horse power that though it may be a small amount every little bit helps.

Considering that it started with 20-22 HP and is now around 35HP that even if I only gain 1 HP by doing this that will give just a little bit more.
And if you are on a narrow track the hole shot is everything.

Thanks for the tip!!!!!

[Bill Martin]

Ok I just talked to a friend and he has a 05-450 carb with only a few hours on it and I can have it for $25.00.
Please correct me if I'm wrong but now I need a 450 throttle cable and a hot start plug(OEM).
Is that all I need to buy?
I was thinking of looking on eBay for a spare intake boot to mod so if I want to put the stock carb back on I can use the original intake tube.

I don’t have the carb in hand yet so I haven’t seen it but what should I use to plug the vent hole on the top?

Is there a adapter for the intake tube or the air box? Or do I just sand the inside of the tube a bit and just cram it in?

Thanks Bill

[buster024]

http://www.exriders.com/vbb/showthread.php?s=&threadid=314423&highlight=carb

[Bill Martin]

Thanks Buster 024 I can do that.
I put in a PM to see if he still has the adaptor available.

That was very helpfull. Thank You.

[exracer416]

im about to do the same mods to my motor how does it rip in the midrange??

[Bill Martin]

I don't have the final mods yet, Hang in there I'll post the results when I’m done.