rev box? which ones work good

[capncharlie]

i was thinkin of gettin a rev box but i don't want starting problems. some of you guys have said that big gun and white bros are no good. what about rev max?

its a 01 400ex with full pro circuit exhaust and a uni filter w/o lid

[Chin_Chilla]

I've had my Big Gun CDI for almost a year now...no problems. I don't know where you heard they were junk but no regrets here....

[Wheelie]

IMO--Don't waste your money on a rev box on an internally stock 400ex. The engine quits making power at about 7k rpm, stock rev limit is 9100 rpm. On a modified engine, however, there could be gains.

[ImplodedMindZ]

Iv got a Magnum CDI and iv had no problems starting w/ a somewhat low battery or any problems gettin it cranked over in the cold weather. It gets the job done.

[ride_red666]

IMO rev boxs are useless on a stock motor. ive got the procom cdi box and it works much better with engine mods. stock rev limit is around 8250. rev boxs up the limit to around 9200. u might notice a slight difference but not much on stock motor.

[Wheelie]

The stock rev limit is 9100, rev boxes bring that up to 10,100-10,200.

[capncharlie]

ok, thank for the help. so i'd be better to put a piston and a cam in first. i don't really want to bore it out, just a high comp piston and a stage 1 hot cam.

[baker400ex]

i have a DynaTech rev box and it works great for me and i have a pipe filter and dynojet kit and a hotcame stage 2...it made a world of difference

[capncharlie]

some of the rev boxs say they improve the bottom and mid range by advancing the stock ignition. do you guys see much low end improvement?

[Ace Sixx]

Powroll says:

"Many aftermarket CDI boxes on the market today are actually stock Honda XR250R boxes! The unmodified XR250 box will give you about 800 more rpm on top and a faster ignition curve. You can purchase this directly from your local Honda dealer and save money.

Order: CDI for Honda XR 250 1992-2004"

:cool:

[400exrider707]

Originally posted by Ace Sixx
Powroll says:

"Many aftermarket CDI boxes on the market today are actually stock Honda XR250R boxes! The unmodified XR250 box will give you about 800 more rpm on top and a faster ignition curve. You can purchase this directly from your local Honda dealer and save money.

Order: CDI for Honda XR 250 1992-2004"

:cool:


and then using these is where all of the starting problems come with....


A rev box can do two things... raise the limit, and advnace timing..

I would only recommend TC racing, or GT Thunder, as they are the only two Im aware of that are not XR250 boxes. Everyone else that I know of is junk, because you will experience starting problems... it is made to turn over an xr250 motor and do it slower if I remember correctly, so if your battery isn't fully charged or its cold out... forget about it you will need to be bump started.

[400ex7]

If your willing to fork out the money the Vortex x10 is a good box. My x10 has worked excellent. It has ten different ignition curves including the stock 400ex curves. The rev limit is raised to 10,800.

[Ace Sixx]

Originally posted by 400exrider707
and then using these is where all of the starting problems come with....


A rev box can do two things... raise the limit, and advnace timing..

I would only recommend TC racing, or GT Thunder, as they are the only two Im aware of that are not XR250 boxes. Everyone else that I know of is junk, because you will experience starting problems... it is made to turn over an xr250 motor and do it slower if I remember correctly, so if your battery isn't fully charged or its cold out... forget about it you will need to be bump started.

Interestingly, the latest issue of QUAD Magazine touches on CDI boxes and problems starting when battery voltage is too low.

[j450rking]

i have a rev max and i love it starts just like it was never there and you can get them on ebay for $40!!!!!!!

[400exrider707]

Originally posted by j450rking
i have a rev max and i love it starts just like it was never there and you can get them on ebay for $40!!!!!!!

Give it time, you will need it to start and it wont....just wait and see:o

[400exrider707]

Originally posted by 400ex7
If your willing to fork out the money the Vortex x10 is a good box. My x10 has worked excellent. It has ten different ignition curves including the stock 400ex curves. The rev limit is raised to 10,800.

Ahh yess, the programmable ones, good box, as well as the DYNA boxes, but rather pricey. The ones I pointed out were only non-programmable ones...but yes the vortex is supposed to be good too.

Originally posted by capncharlie
some of the rev boxs say they improve the bottom and mid range by advancing the stock ignition. do you guys see much low end improvement?

I'd like to know this as well.

[Pappy]

i would agree on the GT thunder unit. it works very well


as far as the performance, most folks have expressed better bottom and mid pull with this unit(im sure due to the ignition curve) and the starting issue is not a problem as it doesnt affect it like the XR box.

id say if your a xc, trail or play mx rider where you are not at WOT, its a worthwhile mod.(in reference to the raised rpm limit)

Originally posted by Pappy
i would agree on the GT thunder unit. it works very well


as far as the performance, most folks have expressed better bottom and mid pull with this unit(im sure due to the ignition curve) and the starting issue is not a problem as it doesnt affect it like the XR box.

id say if your a xc, trail or play mx rider where you are not at WOT, its a worthwhile mod.(in reference to the raised rpm limit)

Interesting.... I may check it out, since I ride mostly XC.

Tho here's what I don't get...

If its a "rev box" wouldn't the main benefit be at WOT? How much benefit do people experience at lower RPM's?

Most of my trails / XC riding I'm prolly 7500 RPM or less.

[400exrider707]

Originally posted by garandman
Interesting.... I may check it out, since I ride mostly XC.

Tho here's what I don't get...

If its a "rev box" wouldn't the main benefit be at WOT? How much benefit do people experience at lower RPM's?

Most of my trails / XC riding I'm prolly 7500 RPM or less.

Well like I said before it can do two things... raise RPM limit, and changed ingition timing/curve.

The raised RPMS is obviously for high RPMs, but the ingition curve will help all over.

[Pappy]

Originally posted by garandman


If its a "rev box" wouldn't the main benefit be at WOT? How much benefit do people experience at lower RPM's?

Most of my trails / XC riding I'm prolly 7500 RPM or less.


this is where the ignition curve offers a benefit. i didnt think i could tell a difference over GT Thunders versus the Big Gun, but I tried it and my seat dyno was pleased:p and it got rid of that god aweful starting problem. i actually removed my big gun box and reinstalled the stock one even after i had changed the pilot jet.

Thanx, Pappy and 707.

:)

Now...off to GT Thunders website....

[ATVnewbie]

Seems better than the stocker, and I did notice that I had to richen up the carb some as it was lean just switching the CDI, btw, as for the starting problem I started mine in 20-30 degree temps with no problems yet knock on wood.....John