Cdi box

[400ex7]

I know this has probly been established on another thread but does anyone know the best cdi for a 400ex. I been thinking about the vortex or the dynatek but if I change my mind because of the price what is another good cdi? How is the gt thunder?

[Rip_Tear]

Stock is good... Most other CDI's create problems for starting in cold weather or create other possible problems and from what I've read do no do a lot.

[450Rchaser]

I have a d&t dyno cdi box. No trouble out of it.

[cals400ex]

i would get the gt thunder. dyna was having problems with their 400ex box failing.

[#8red]

i've got a whitebros. cdi - the price has really gone down on them - I don't know if it's my cdi or motor kit or both combined but my battery has to be pretty charged when it's cold (also no choke on my 39mm carb) - but the w.b. cdi is great

[hydromatikman]

After I installed a 426 kit and stage 2 hot cam in my '00 400ex I also put a white bros cdi box in. I personally hated it. It simply wouldn't run very well at low rpm and had to constantly keep the battery charged to full capacity in order for it to start. I then switched back to the stock cdi box and had no problems at all.
Just my .02

[400ex7]

Hey #8Red, its your cdi box thats causing the trouble. I've heard alot of bad things about the white bros rev box. I heard it was just a box from the xr400 dirt bikes. I heard they will kill your battery when its cold and give the 400ex starting problems.

[#8red]

I don't have any probs w/ my w.b. cdi - in fact I'd recommend it - the power curve is perfect - plenty of low end - just when my bike sits for a few weeks I know to throw the charger on it for a few hrs. to get it started the 1st time -

[Joecool1264]

I just bought a 416, stg. 1 cam, pro crit. t-4, and a WB box. It runs like a scalded ape. No starting issues yet.

[cals400ex]

your best bet would be too stay away from the curtis sparks and WB boxes. i have been there once and i would never go back. i then used 2 different boxes from gt thunder and both were far superior. i haven't tried the big gun one. some people claim they have starting problems, others say they don't. i hear the TC box is good too but i have not tried that one either...

[quad71]

tc racing works great ihave a 440 and with the white brothers in the winter i would have to start and warm the engine with the stock box and then put in the wb box. tc racing no problem and putting out 40 horsepower.

[QuadJunkies]

Originally posted by 400ex7
I know this has probly been established on another thread but does anyone know the best cdi for a 400ex. I been thinking about the vortex or the dynatek but if I change my mind because of the price what is another good cdi? How is the gt thunder?
GT Thunder - GREAT!! I have have no issues what so ever