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.