Rev Box?????

[JAM400ex]

im thinkin bout gettin a rev box....engine is stock with stock exhaust still on....do yall think a rev box is a good investment???

[2muchquad]

no,your stock engine probably wont make anymore power with more rpms.It might but doubt it.If you had headwork and a cam and free flowing exhaust i could see but the returns with a stock engine would be minimal imo.you would probably get more bang for you buck with a $25 degree key for your flywheel.It advances your ignition...do a search on here;)

[rcatvrider]

Originally posted by 2muchquad
no,your stock engine probably wont make anymore power with more rpms.It might but doubt it.If you had headwork and a cam and free flowing exhaust i could see but the returns with a stock engine would be minimal imo.you would probably get more bang for you buck with a $25 degree key for your flywheel.It advances your ignition...do a search on here;)
agreed

[sprayedgt]

X2. The advance key is a inexpensive part and about a 30 min install. I would take the money you would have spent on the rev box and invest it elsewhere.

rev boxes need to stay on the bike they were made for...

[400exrider707]

Only need for a rev box is if you're hitting your max RPM and still have MORE power, 99% of the bikes I've seen with rev boxes do NOT need them. Look at the stock power curve, the power is falling off far before rev limit.

Originally posted by 400exrider707
Only need for a rev box is if you're hitting your max RPM and still have MORE power, 99% of the bikes I've seen with rev boxes do NOT need them. Look at the stock power curve, the power is falling off far before rev limit.

idk why people sa this because if you look at a dyno graph the power doesnt drop like people think its not bad

[buster024]

idk why people sa this because if you look at a dyno graph the power doesnt drop like people think its not bad

I agree. I don't have a dyno to prove my performance gains, but I noticed a very distinct difference in the available rpm's on my bike once I installed a rev box. It's nothing I feel in the low or middle end, but during wide open throttle performance on the dunes, or flat out haulin' *** I have more revs than I had prior to the new rev box. Plus, being able to start in reverse is always a nice feature.
In my opinion they aren't the near the top of the upgrade list, but they aren't a waste of money.

[bigbad400]

they dont just give you more rpms they also give you a stronger spark and a more steady spark than the stock cdi. go to ebay and look the AMR stage 3 revbox and coil combo. they are great deal.

rev boxes and the stronger spark not really but a coil can do that. Most rev boxes advance the timing because advanced timing makes it pull longer and higher but the advance is pretty small and not very noticable like 6 degrees is.

[400exrider707]

Originally posted by FoxHondaRider
idk why people sa this because if you look at a dyno graph the power doesnt drop like people think its not bad

The point is it drops... and with more revs, its just going to drop more. Sure a few extra revs might be OK for rounding that last corner into the finish line or something, but realistically its not needed, the power is already falling off, and with more RPMS the power is going to continue falling...


Aside from all this, lets talk rev boxes on the 400ex...

90% of the boxes out there are just old XR250 boxes... they dont work well on the 400ex, and WILL cause starting issues. There are many threads about this.

As far as I knew last, the only decent boxes for these bikes were the TC box and the GT Thunder box, they were the only ones MADE FOR THE 400ex, the others are just rebadged xr boxes.

[DuwBra]

Originally posted by bigbad400
they dont just give you more rpms they also give you a stronger spark and a more steady spark than the stock cdi. go to ebay and look the AMR stage 3 revbox and coil combo. they are great deal.

Agreed, I got mine and my quad starts way better than before and its snappier, plus its nice to have those extra rpms.

[400exrider707]

Originally posted by DuwBra
Agreed, I got mine and my quad starts way better than before and its snappier, plus its nice to have those extra rpms.

It doesn't start easier, it's just in your head. Trust me, it will get worse. As soon as the battery starts getting any little bit of weakness to it, you'll see. It will stop working, guaranteed.

[400ex28]

I had a magnum rev box for years on my 400ex and never had one bit of starting issues. even in the cold? I never even bought a battery for that thing it was still the original from 2002.

[DuwBra]

Originally posted by 400exrider707
It doesn't start easier, it's just in your head. Trust me, it will get worse. As soon as the battery starts getting any little bit of weakness to it, you'll see. It will stop working, guaranteed.

Then give me a good reason why my throttle responce and starting got better after I put it on. Its not in my head, it's physically better, there's no way for me to think any different when it really did get better.

Originally posted by 2muchquad
no,your stock engine probably wont make anymore power with more rpms.It might but doubt it.If you had headwork and a cam and free flowing exhaust i could see but the returns with a stock engine would be minimal imo.you would probably get more bang for you buck with a $25 degree key for your flywheel.It advances your ignition...do a search on here;)

A big gun rev box advances the timing giving you a extra 2hp plus around 1000 rpm.

[mooseracerX]

Originally posted by 400exrider707
It doesn't start easier, it's just in your head. Trust me, it will get worse. As soon as the battery starts getting any little bit of weakness to it, you'll see. It will stop working, guaranteed.
Agreed. My quad w/ a WB will not start worth a crap. You have to hook a jump box up to make it start when its cold. =\

Although most of the Big Gun Rev Boxes I've seen eliminate the rev limiter all together.

Originally posted by Boris The Goat
A big gun rev box advances the timing giving you a extra 2hp plus around 1000 rpm.

false i saw a dyno chart it gained about .3 HP. your best bet it sparks 6 degree key and their 1000rpm rev box. you will sure feel it

Originally posted by 400exrider707
It doesn't start easier, it's just in your head. Trust me, it will get worse. As soon as the battery starts getting any little bit of weakness to it, you'll see. It will stop working, guaranteed.

I have only heard of white bros rev boxes doing that.

[rcatvrider]

The best solution i have heard for those who find it hard to start is to tape or zip tie the stock one right on or next to it and plug it in before starting. On 05's the hood pops off and the rev box is right there, not sure about the other years.

[400exrider707]

Originally posted by Boris The Goat
I have only heard of white bros rev boxes doing that.

PSssst.... little secret.... they're all the same.

Other than the two I've posted and maybe one or two I dont know off the top of my head, but all the big name ones... big gun, white bros and the likes... they're all the same.

[mooseracerX]

That's true, my WB wasn't even made by WB it was made by the same company that made the stock one.

[2muchquad]

It doesn't start easier, it's just in your head

LMAO:D

I agree though,99% of the boxes are xr boxes.Its funny people will believe anything the manufacturers claim,such as 3 hp for a big gun cdi...get real.Thats like instead of race porting i'll just slap on a big gun cdi instead.If i can find a schematic for a 400ex cdi,i would do the same thing i did to my 300ex cdi,i drilled out a capacitor and did away with the rev limiter altogether..now thats what im talkin'bout baby boy:D

Originally posted by 400exrider707
PSssst.... little secret.... they're all the same.

Other than the two I've posted and maybe one or two I dont know off the top of my head, but all the big name ones... big gun, white bros and the likes... they're all the same.

Ya well maybe I'm not the one going out buying rev boxes but here on exriders for years I read a lot of people say their WB rev box had starting issues and that others didn't. And the only time people have trouble is normaly in winter or if they let their quad sit a while letting the battery charge go down.

A stock 400ex power peaks at like 6500-7000rpm with 27hp and after that power starts dropping. If you rev it out to 9000rpm your power had already dropped to like 18hp. Thats why a rev box does no good on a stock 400ex.

And wether it starts better or worse with the rev box im sure it started just fine b4 the rev box was on their.

[DuwBra]

all I said was you cant tell me mine didnt make a difference when I know it did. Las time I checked. . . . yeah you weren't there.

Originally posted by Boris The Goat
A stock 400ex power peaks at like 6500-7000rpm with 27hp and after that power starts dropping. If you rev it out to 9000rpm your power had already dropped to like 18hp. Thats why a rev box does no good on a stock 400ex.

Going to have to say wrong again why are so many of you thinking like this? Do you really think the power drops off that bad? I have a dyno it seems to read high but it still shows the curve and what not. It peaked at 30HP and at 9k 24HP so 6 HP was dropped from 7100RPM peak to 9000RPM almost Rev limiter. Still making 21HP isnt bad its the power you make at 5800RPM. Put a new cam and advance the timing and that 6HP drop would probally be more like a 2 or 3 HP drop. Rev boxes are good if you want to rev it out that last bit to make the turn or hit a jump something where shifting would drop you too low and you bog.

[400exrider707]

Originally posted by FoxHondaRider
Going to have to say wrong again why are so many of you thinking like this? Do you really think the power drops off that bad? I have a dyno it seems to read high but it still shows the curve and what not. It peaked at 30HP and at 9k 24HP so 6 HP was dropped from 7100RPM peak to 9000RPM almost Rev limiter. Still making 21HP isnt bad its the power you make at 5800RPM. Put a new cam and advance the timing and that 6HP drop would probally be more like a 2 or 3 HP drop. Rev boxes are good if you want to rev it out that last bit to make the turn or hit a jump something where shifting would drop you too low and you bog.

6hp drop is huge on a motor that only makes 30hp. That's a 20% decrease. I think you're missing the point, thats all it drops on a stock box... now add a higher rev limit and say it adds 1000rpms. If your curve keeps dropping as it did from 7000rpm to 9000rpm, you'd lose another 3hp on top... and that's only if the power was linear, you'd realistically lose more than that.

DuwBra - You can believe whatever you want, but until you dyno stock and then dyno with the aftermarket box, you have no proof either. People tend to "feel" things that are not there. I'm not saying it doesn't feel different, you're right I wasn't there, all I'm saying is you will have starting issues when the battery gets weaker or it gets colder out.

[DuwBra]

haha you some of you people are unbelievable. I could say it rained today where I'm at and you'd argue that's not what the weather said so I dont believe you. It made a difference! Period. When I put mine on there was a noticeable and still is a noticeable difference six months later. So think all you want, mine worked. Sorry that yours didnt.

[Chukkinsod]

I had a WB box and it was a pile...I threw it across the yard. would not start at all (with full charge) Ran stock box for a while had no issues except hit limiter often....even when short shifting (drag race). I since then went with a procom box.....its winter here now and it started up with next to no charge. I dont think it adds power, but in my case it gave me just a little more time before rev limit.......

[DuwBra]

Thats what Im sayin Chukkinsod, finally someone who says something sensible. Mines really a procom and it does fine, I like it. Gives me a few more revs and mine starts easier with it.

[400exrider707]

Originally posted by DuwBra
haha you some of you people are unbelievable. I could say it rained today where I'm at and you'd argue that's not what the weather said so I dont believe you. It made a difference! Period. When I put mine on there was a noticeable and still is a noticeable difference six months later. So think all you want, mine worked. Sorry that yours didnt.

I never put one on my EX, there was no need! The only ones I'd use are the GT Thunder box and the TC national.

Give it time... if I'm not mistaken procom was one of the worst ones... I believe about only 30% of those boxes worked upon delivery, they were a big ebay item...

I'm glad yours is working out for you. Some of them advance timing a touch, so that is probably what you're feeling, but just trust me that you will have starting issues later. It may not be now, but it will happen. I only hope that when it does you are man enough to post it up in here! Good luck with it!

[DuwBra]

Oh there ya go get one more post in about how much you know about quads, make sure everybody knows that you know it will fail later on.

[katch26]

hes right though......believe what you want theres a reason its the 99 dollar special. Procom makes the majority of them and a high percentage of those fail. I guess if youre balling you can roll the dice on youre expensive toy but I have one and it blew my one way bearing.
http://i44.tinypic.com/10fo038.jpg

see how the curve peaks the same?, who cares that you can rev out a bike all the way down the power loss ramp.

An extra 1000 rpm of less power arent going to help you clear that double any easier....sorry but youre better off staying off the rev limiter. With all that being said that still doesnt even begin to cover what could go wrong like floating a valve breaking a valve spring and the $$$ that would cost you. The fact that youre getting so bent up about it really just shows that deep down you know you bought snake oil.

[400exrider707]

Originally posted by DuwBra
Oh there ya go get one more post in about how much you know about quads, make sure everybody knows that you know it will fail later on.

I'm not here to tell anyone anything but YOU. I'm just trying to beat it into YOUR head...

Didn't mean to offend you bud, I'm just trying to help.

[leasureryan]

Originally posted by 400exrider707
I'm not here to tell anyone anything but YOU. I'm just trying to beat it into YOUR head...

Didn't mean to offend you bud, I'm just trying to help.
Amen...I'm with the smart guy here on this one. I mirror his words.

I'm pretty sure that all ANY of these boxs are is a stock XR250R CDI box with a name brand lable slaped on it. I'm getting ready to do a major rebuild on my 400...and the thought of buying one of these NEVER even crossed my mind. I don't ride enough in the 8,500-10,000 RPM range to give a **** if it's still going to be pulling. I ride mainly in 1,000-8,500 like the rest of the smart people with dependable good running, well built bikes!



only reason I can think the "Duwbra's" quad ran better afterwards is
A. Stock one was defective
B. All in his head

For me you gotta use those upper RPM because the next gear wont lug you around the turn quick enough some turns if I cant round in 3rd i'll shift to 2nd into the turn and as soo as i'm done sliding around it back to 3rd and pull. I tag the rev limiter over whoops or small bumps at times i'll be pulling and the rear will kick up a little and it will tag it then the tires touch ground and it keeps pulling

[DuwBra]

Originally posted by leasureryan
only reason I can think the "Duwbra's" quad ran better afterwards is
A. Stock one was defective
B. All in his head

I dont give a darn about anything else, all im telling you is mine started and ran better and your telling me its all in my head when you have no clue. None of you rode it before and after so how could you even think to feed me this crap that I'm imagining things. Of course you offended me your telling me that my quad is not doing something that it is and you dont even know. haha, just how I thought it would be on this site, a few people would be understanding and open to ideas and the rest act like there's no other way but their own and they know everything.

[400exrider707]

Originally posted by DuwBra
I dont give a darn about anything else, all im telling you is mine started and ran better and your telling me its all in my head when you have no clue. None of you rode it before and after so how could you even think to feed me this crap that I'm imagining things. Of course you offended me your telling me that my quad is not doing something that it is and you dont even know. haha, just how I thought it would be on this site, a few people would be understanding and open to ideas and the rest act like there's no other way but their own and they know everything.

You'll soon realized that the internet is just that, the internet. Open to everyone to express their opinions and beliefs. If you want people to believe something against the norm, you're definitely going to have to prove it or just deal with the fact that no one believes you.

Having said that, I've already agreed it may have done something because of advanced timing. Also in foxhondariders case he can use the extra RPM's for certain tracks he rides at... that's fine. All I'm saying is it will have starting problems. Why is it you dont believe that? There are numerous posts about these boxes failing.

[2muchquad]

well the bottom line is,to each his own.What might work for some people might not work for everybody else(such as cdi's..lol).Some people say dyno jet kits are garbage,me i happen to like dyno jets and their needles and their sizing system..but thats just me:)

[DuwBra]

x2 2muchquad, i say one thing and people go nuts just because its not what "usually" happens. Im done with this thread.

Originally posted by DuwBra
x2 2muchquad, i say one thing and people go nuts just because its not what "usually" happens. Im done with this thread.

its hilarious when it happens though. i've done it for fun on here a few times idk why but its so funny to see people flip out over something on the internet or if you pretend like your flipping out just watching the responses haha priceless. Look at my thread I made blew a head gasket today. It was all a joke I started and then people kept going on and on and its still going on lol

[scuzz]

Fox,

I believe what makes 'em angry is the wasted time and post-whoring.

[sc400ex_rider]

i built my motor and kept the stock cdi just for insurance not to float a valve and i have kibblewhite springs. i got the sparks key and it made the throttle response snappier. i have stock gearing and have only hit the factory rev limiter a couple of times when i missed a gear or found neutral. i really zinged it and was glade i had it. i dont want my motor to rev any higher than 9800rpm. but people will always do there own thing. theres a reason why used 400ex heads sell for $200 on ebay, strong demand. LOL

Originally posted by scuzz
Fox,

I believe what makes 'em angry is the wasted time and post-whoring.

good then i shall continue for you

[rob_990]

lol