400ex carb on 300ex?

I was wondering if a 400ex carb would work on a 300ex. My neighbor has one for sale and if it works, the i'll buy it.

[NVR2L8]

Yea, it'll work, but it requires a different intake boot. I also have a 400EX carb that I want to put on my wife's 300EX, but just haven't had the ambition and/or time. Anyway, I'm pretty sure the 400EX carb will bolt right onto the engine intake adapter, but since the filter side of the 400EX carb is larger, it won't fit on the stock 300EX intake tube. Go to your local Honda dealer and order a 350X intake tube...that's the one you'll need to adapt the carb to your machine. BTW, you'll also have to rejet the 400EX carb for your 300EX.

Would the 400ex carb give me a power increase?

[NVR2L8]

I've heard it's helps to provide a slight increase...just don't expect a large power gain. I've heard it provides more significant gains for a 300EX that has internal motor mods.

Well i'm looking into a 352cc kit for the 300ex from Powroll. Maybe i should go ahead and get the 400ex carb from my neighbor and order the air tube for the 350x and just keep them until i get it done.

[NVR2L8]

I've dealt with Powroll in the past, and I think they are one of the best engine builders out there. You might want to call them and talk to Pam...she would be able to tell you if the 400EX carb would work well with their 352cc kit.

NVR2L8, have you heard anything about that 352cc kit from Powroll? I'm starting to race motocross and i went over there with my stock 300ex on a practice day, and my friend brought his stock warrior, and he couldn't get infront of me mostly because of the Honda's handling, but everyone else blew me off the track. So, i need some power.

[NVR2L8]

Nope, I haven't heard anything about their 352cc kit. My experience with Powroll dates back quite a few years ago...a friend of mine with a 250X had Powroll rebuild the engine while also doing a minor performance hop-up. Not sure exactly what they did, but it wasn't a full-blown race engine upgrade...I believe it was just a slight overbore with a higher compression piston. Anyway, the guy consistently flogged the dang thing, and it just kept running no matter how hard he abused it. My recent dealings with them concerned a lot of technical questions when I was looking to upgrade my 400EX, and each time I contacted them they were always very helpful, even though I ended up having a local guy do the motor work. Anyhow, they have a very good reputation when it comes to their products.