I just put on my Lectron 36mm carb from TC Racing. It definitely goes a little better. I took the whole airbox off and it screems now( can finally beat some of the modded Banshees now) The only problem is how the carb fits. You have to install it so it's at the 1'oclock position so the throttle cable will fit in the stock groove under the gas tank. And the air filter tube doesn't fit on the carb really good.(doesn't go back as far as i'd like) Otherwise it's a good carb, but i wish i would have tried the Keihen 39mm! Anyone try the 39mm? The best thing you can do to the 400ex is a higher commpression piston(big bore or stock bore) and a cam. I put a Ross 11:1 lightened piston with a XR400 head gasket and a WebCam 450/451 grind cam and it turned my bike into a rocket.
oi

 

I have a 36mm lectron on my 400 and it works awesome. If you follow the directions that TC racing gives you, it will work fine. Did you take off your airbox, or just your airbox lid? It says to make a bracket for the airbox, the bracket makes it push in closer to the engine about an inch. Also you have to remove that big white tube from the airbox. The only problem I have had with mine is adjusting the idle, but that is now under control. As for a 39mm, TC racing said it is not as good as a 36mm, the 36mm hits much much harder.

 

Don't know much about the lectron except that it's pretty popular.

What do you guys know/think about the new Edelbrock? It's supposed to be out next week.

Dennis

 

I have one on my TC405ex. I have the same problem with the gas tank hitting the top of the carb cable. Only bad thing about Lectron carbs is keeps the slide polished they can hang up after a while.

 

Just another thought.. I have the Lectron carb on the TC405ex and TC also modded the thumb throtle housing in order for the carb slide to open up all the way. How does this ecffect the 400ex does the slide open all the way without modifying the throttle housing??

 

you have to grind the stop inside the thumb throttle. That is the only way it will open all the way.

 

a dremal works real good for that