I'm thinking of buying a rev kit box for my 400ex. I think i'm going to go with one from CT racing. But can someone tell me if this mod really helps? Is it a simple project to do or will it require me to take it to a shop to have it put on?

 

It's pretty simple to install. The cdi box is under the nose plastic and sits in a rubber boot that is hooked to the frame. There are 2 plugs with side clips. Take a look at it it's self explainatory. I've got a new rev box that I'll sell for $60. I live in St. Louis and go to St. Joe all the time. If interested e-mail me.

jkatv400ex@aol

 

Okay pudjumper I gotta know...why are you selling it?

 

Aaron i have a friend that had one and it dosn't help unless.It moves the rpms to 10000 right look at power curve. It will only help if you put a High duration cam in it so the power comes on later

 

Aaron i have a friend that had one and it dosn't help .It moves the rpms to 10000 right, look at
the stock power curve. It will only help if you put a High duration cam in it so the power comes on later.Sorry i didn't read the first response it didn't make sense

 

I use a White Bros rev box, it really does make a difference on steep climbs, I can't tell any differnce on the flats though.

 

I don't do alot of climbing. Quite a bit of flat trails at top speeds though, and i hear that the give you more top speed. Also I race TT and on one straight way my bike hits the rev limiter in 3rd and i have to switch to 4th for a split second and then drop back to third. Will the after market CDI help me with this?

 

The only way you would get more top end from the W.B. cdi, is if you are already bouncing off the rev-limiter wide-open in fifth gear right now.The rev-box allows the motor to spin an extra 1200 rpms. If you can't hit the rev-limiter right now in fifth, don't bother buying one. If you have no mods done to the bike yet, i would actually buy a 14 tooth front spocket for it so it will all the way to the rev-limiter. you'd be suprised at the difference from a 14tooth front sprocket.

 

I don't think it will help you. I have never hit fifth wide open with mine, but I can certainly see a major difference wide open in 2nd or 3rd while climbing. All my riding is in the high desert...never MX or TT. Try the 14t sprocket...it makes a huge difference in all gears except 5th