350x carb VS 400ex carb

[austin1990]

I think there might be other threads with people who have switched carbs but i haven't been able to find a thread with all the info in one, so here it goes...
Who have swapped the carbs?
How does it increase performance?(if it does)
Whats involved in swapping them out, does a 400ex carb just swap in without any mods like air tube, throttle cable, jetting, ect...?
Any problems that anyone ran into when doing the swap?
Hope this thread helps people (including me)

[Dirtcrasher]

There are threads on it, people do run them because they are close to size, jet up and go and have a fuel accelerator. All depends on your mods. I'd like to have one of my NOS heads ported and then add a 41mm FCR carb.......

[TatTooL23]

They r only .5mm bigger then stock 350X carb I think but u get the accelerator pump. Helps starting it and throttle response. Use stock throttle cable. Fits tight but will go in there. Only thing I had to do was heat my intake tube in the one spot where the choke arm of the 400ex carb is. The tube would press against the choke arm pivot point not allowing it to snap back to regular position. So I just heated that one spot and used the but end of a screw driver handle and made a little dimple in the intake tube. You may have to mess with jetting depending on what u gave done for mods.

[murfman]

They r only .5mm bigger then stock 350X carb I think but u get the accelerator pump. Helps starting it and throttle response. Use stock throttle cable. Fits tight but will go in there. Only thing I had to do was heat my intake tube in the one spot where the choke arm of the 400ex carb is. The tube would press against the choke arm pivot point not allowing it to snap back to regular position. So I just heated that one spot and used the but end of a screw driver handle and made a little dimple in the intake tube. You may have to mess with jetting depending on what u gave done for mods.

This^^^

I also have an aluminum adapter to use the 400EX intake rubber, but it is 1/2" thick so it makes the carb an even tighter fit, I had to trim the bottom of the plastic throttle cable cover to clear the frame. I like the throttle response and once jetted it pulls strong and starts easy.

[austin1990]

Great info guys, thanks