400EX carb on 300EX, need info pleez

[kc 300EX]

My cousin just got a Lectron Carb for his 400, so he is giving me his stock carb for like, nothing.

SO, I want to put it on my 300 of course, Ive heard its possible and a lot of people have done it, so I need to know what is required and what is involved in doing it. I know Ineed a 350X airboot and I plan on getting one as soon as I can, but other than that I am in the dark, any body who can help as far as jetting and other mods I need to do, i would really appreciate it, thanx guys

Looks like you have everything covered. You just need to put the carb on and rejet. The 350x airboot is tight, but it does go on. Just start with the stock jets and go from there. You will be amazed with the performance gain especially if you have mods done to your engine. Good luck..

[330exracer122]

u do not need a 350x boot it just give u a lil more.. i don't use one cause im to lazy right now

[liltazz]

u dont need the air boot it will fit right on the stock boots. the needle should be lifted, move one notch down and start with a 175 main jet.

[300exazzkikr]

A 400ex carb works best if you have mods on your engine..If you have mods then you'll see the most gains..

[kc 300EX]

My only engine mods are a Full WB Exaust and Wiseco Std Bore 11:1 Piston.
My quad is actually all apart right now, and as soon as I get the rest of the parts the new piston is going in.

When I add the carb, I should start with stock 400EX jets youre saying?? a 175 sounds way too rich to me, thats jetted up from stock right?? I thought I would have to jet down?

I guess Ill go out and buy a bunch of jets and see what works, I got a box of plugs already, Im prolly gonna get the 350X airboot anywayz, thanx guys

[300exazzkikr]

You should be good...but don't qoute me on this but 175 is way too rich..ask around on here who have done this and they'll give you an idea where to start..145 sounds familiar..but not sure..

[liltazz]

i had one on my old 300ex 11:1 and WB race cam and the stock 148 is way to lean. you cant even get pas half throtle. start high and then drop down. and the carb has to be fine tuned before every ride. it is a pain in the but to get set up.