When I ride my 400ex it only wheelies eaisily in 1st gear and a little 2nd. I still smoke all the warriors and 300ex no problem but the front end jus doesnt come up easily. I figured it could be running lean or could use a different jet. i believe it has a 142 main jet with just a k&n airfilter. Also, when I took the sirbox lid off it had less power and got really hot. What should I do for it to pull up quicker? Thanls for suggestions.

 

Pull the plug. If its white-lean-then you need bigger jets- if its black-then you need smaller jets-rich and if its brown then don't touch it.

 

I kind of have the same problem. I'm heavy, and it's work for me to wheelie any bike, so I can't fault it much there. But the worst thing is it bogs slightly in 1st and 2nd gears, and a little in 3rd. It's kind of like a 2-stroke power band thing, where it bogs a bit then the power hits and it takes off (but, at least once you pass that bog, the thing flat out rips!) It has gotten me in trouble a couple of times when I was setting up for a jump. It bogged on the takeoff (medium sized double jump) and I had to really stretch to make the landing ramp.

Anyway, I've played with jetting and everything else, and it just hasn't improved much. The dealer has played with it and they couldn't improve it either. I think it's just a combination of mods that the engine/carb just doesn't like. So, I'm just going to get an Edelbrock carb. These are known for low end response, so I'm hoping that will be the cure????