rev box question

[doiniton4]

Have stock 400ex with what I was told is a WB rev box on it.The box looks like factory stock with a WB engraved on it.Having a hard time starting in colder weather.Want to go back to stock box as I have no need for the WB box if that is what it is.Jetting is good.Is this a WB box? Thanks

[Craig02]

Yes it is probably a wb box, most aftermarket cdi's look just like the stock ones. If you need a stock cdi, I have one for sale.

[komatsu kid]

try searching for rev box,from what i hear this is the proplem with these,thats why i havent bought one

[RED121572]

Ive had two different boxes. Ive had the XR250's and the WB's. (rumor has it they are the same)

Ill get bashed for this, but I disagree on the starting problem. Up your pilot jet and it should fix the problem. (worked on my machine) I got rid of mine cause of the extra RPMs.... My valves were screaming for mercy.

[trailburner]

yes, it's a WB box. I had one, if the battery doesn't have FULL charge it will not start the bike. sold mine & put the stock one back in ,starts fine now.

[Giz400ex]

Originally posted by trailburner
yes, it's a WB box. I had one, if the battery doesn't have FULL charge it will not start the bike. sold mine & put the stock one back in ,starts fine now. I recently bought a Sparks box and I had the same prob. Granted my battery is almost 5 years old but it still starts with the stock box. When installing the CS, I had to charge the battery for a couple of mins and then it started fine. Do all of these aftermarket boxes do this?

[doiniton4]

[QUOTE]Originally posted by Craig02
Yes it is probably a wb box, most aftermarket cdi's look just like the stock ones. If you need a stock cdi, I have one for sale. [/QUOTE ] How much do you want for your stock box?

[H440exconfused]

I have my stock rev box and my WB, piggy backed together, I live in Michigan and its cold, I start it with the stocker and after the quad warms up I just flip it to the WB. Works for me.

[cals400ex]

Originally posted by Giz400ex
I recently bought a Sparks box and I had the same prob. Granted my battery is almost 5 years old but it still starts with the stock box. When installing the CS, I had to charge the battery for a couple of mins and then it started fine. Do all of these aftermarket boxes do this?


i hear the gt thunder and tc boxes both enable you to start your bike like the stock cdi would. i will probably order the gt thunder box next week.

[F-16Guy]

Do a search for more detailed information, but the WB cdi is an XR250 cdi. It has an "anti kickback" circuit that prevents spark below a certain rpm to keep the kickstarter on an XR250 from slapping the back of your leg. If your battery isn't fully charged (especially on high compression engines), then the starter won't turn your engine over fast enough overcome the circuit; hence the starting problems. I sold mine and went back to stock. Another option is to buy a modified 400ex cdi. You can tell the difference by size, the XR250 cdi is quite a bit smaller. Most places that offer the modified cdi will require you to send in your stock box for modification or as a core.

[SnellCRP]

I think the reason we usually have starting problems with aftermarket CDI's is because of the timing curve that the CDI puts the engine into dosen't complement starting. The CDI mainly adjusts the timing curve and increases the rev limiter for HP gains while the engine is running. My .02.

[duncanracing400]

i have a wb cdi box, and any mod or product u get, u should usualy atleast read the instrucions. yes i know, it doesnt take a genious to put in a cdi box, but u should at least read what comes with it if u spent $110 on it anyways, AND if you would have read it, it says 'quote' "Battery Must Be At Full Charge Before Use." unquote. And y would you not have your battery and full charge in the first place? havnt been leaving the lights on with key on? if you havnt, it shouldnt be like that, or if you have been starting it and not riding it for very long, u should take more care of it bro

if you wanna skip all that mumbojumbo junk, you can just use your wb box in summer,and stock one in winter, because i dont think youll need that little power gain out in the snow.

[QuAdEr 317]

is it hard to start if it is kick start? will it effect starting cuz i have a 250x n was lookin into the sparks high rev box?

[Bennyboy400ex]

Originally posted by H440exconfused
I have my stock rev box and my WB, piggy backed together, I live in Michigan and its cold, I start it with the stocker and after the quad warms up I just flip it to the WB. Works for me.
Thats a freakin' awesome idea!:blah:

[KY Woods Rider]

As F-16Guy said, the easy way to spot the WB and XR250 boxes are by their size, specifically the length. If you look at the little rubber boot that the CDI fits in, the stocker will fill it completely, all the way from the bottom of the boot out to the little strap at the end of the boot. When the WB is fully seated into the rubber boot, there will be approximately (I ain't measured it) a 1/4" gap between the end of the CDI and the little strap on the boot.

As for the hard starting, I've used my WB in temps down to 25º F and have never had any problems with starting. I've never tried it in colder temps though, because I'm usually on a 4x4 playing in the snow if it's that cold outside:D. Of course I don't like half-dead batteries on my quad either:p

[Natertot426ex]

Here is my thought. WB box is junk. Mine will start just fine in the summer but when the temp drops to cold it just won't work. I usually have to wrangle up a stock one from someone to get is started and warmed up and then switch to the WB. I will get a different one as soon as I have the money but don't buy the WB...

[nasty88r]

I just got a 440 ex off a friend it has the WB box on it and does not start in the cold I have not tried the stock box but will do today. If I use the stock box will I notice a big difference with hitting the rev limiter?? Will it hit the limiter while racing through the gear or just when tapped out in fifth gear?? I am new to the EX I have a 330 R and I am now getting into the four stroke thing..

[SnellCRP]

The rev limiter goes by engine RPM not which gear your in so you could hit the limiter in 1st gear if you rev it enough. Also, you won't have to rev the EX like you did the R

[RedEx XCRider]

I have a WB Rev Limiter on mine and i have the same problems....when its cold out side...i have to pull it to start it but if it warm like 70-80 it starts perfectly

[nasty88r]

Who sells the gt thunder and tc boxes because this wb is a pain in the *****. I wanna get the gt thunder if it starts the bike in the cold. If anyone has the gt or the tc how much are they and where can I get one????

[Giz400ex]

Anybody hear anything about the Sparks box??? I'm not sure if its just mine but my Sparks also doesn't want to start when its cold, but I also need to get a new battery.

[nasty88r]

My battery cranks pretty fast as soon as I put the stock box back in it starts right up. I need info on the GT or TC box, price and where to get one????

[SnellCRP]

I have a TC box on mine and it still starts hard unless the quads already warmed up. I just got a higher CCA battery so I'll see how it does.

[Giz400ex]

Originally posted by nasty88r
My battery cranks pretty fast as soon as I put the stock box back in it starts right up. I need info on the GT or TC box, price and where to get one???? Call TC or GT:D

[cals400ex]

Originally posted by Giz400ex
I recently bought a Sparks box and I had the same prob. Granted my battery is almost 5 years old but it still starts with the stock box. When installing the CS, I had to charge the battery for a couple of mins and then it started fine. Do all of these aftermarket boxes do this?


i hear the gt thunder and tc boxes start like the stock box, but i havent tried either one. the sparks box will be hard to start.

[400wheelieking]

How is the big gun rev box? Is that any good?

[y2k400ex]

The Xr 250 box is around $80 from Honda. Then WB, Big Gun, etc slaps a sticker on it or regraves "WB" on it and then charges you $130 for it. Its quick easy money. :devil:

But any ways I had the same problem with mine with starting when the battery is a little low. I Bought a new Yusa battery with more cold cranking amps. Its the same size as the stock batery I'll post the part # later if any one wants it. I have had this setup for over an year with no starting problems at all:D

[Smokin 440]

H440exconfused, how exactly did you piggyback the boxes, if u could tell me that would great, thanks