Should I get a higher rev box?

[bandit390]

Mine has the ims 440 kit, pipe,xr cam,etc... but would a higher rev box help or help it lose reliability?

I got the stock one now.

[phatswinn]

nope, the power band is well before the stock limiter kicks in, so the only thing you would get is a blown motor or bout 3 mph top speed

[JustRace]

agreed. I've got my stock rev limiter back on. No sense in floating a valve by over revving, i'd rather be safe than sorry.

[cheetah]

Throw your $100 into something else.

[Sparks425Ex]

You gotta decide if 3 MPHs is worth 100 bucks plus the cost of your blown motor?

To me its pointless. But i geuss it is up to you.

[oregonrider89]

Powroll recommends it for modified engines. They say it works well with a cam and head work. I haven't had any trouble with mine.

oregonrider89

[Buzzsaw]

If you want that rev limiter go to sevice honda and order one for the XR400 that is all the sparks and WB are.

[danney f]

What about a 300ex with the mods I've got? It hits it way to soon. Is there one for the 300ex, like the xr400 will work on the 400ex.

[Buzzsaw]

The 300 and the 400 limiters are not the some you nave to send it of to sprarks or pro fab to have it done. I sent my to sparks it was like $75 to have it done for my 316.

[KAWSAM62]

hello my 2 cent i have a slittly modified 400 ex ,filter ,jets, fmf slip on, ground pipe, 16 tooth front sprocket and a cdi box off a xr250 , the difference was the advance curve on the timing before when i would hit soft sand the motor would generaly slow down and i would hafto down shift to keep the same speed ! with that cdi on i just turn the throttle and go, no down shifting all may freinds use them and we are not reving the motor any harder it just seems that it pulls better at any rpm, that box does let the engine rev higher but it pulls somuch better that you dont hafto abuse the motor just my 2 cents i like it!

[Ricky g]

The rev box was one of the first mods I did, I was like most, thinking I'm going go faster because the box lets the engine run higher rpm's. Well now the ex is modded to the gills and I took the rev box off and went back to stock, now it starts every time, even in the cold, I think WB made a killing on that little black box, in my opinion it's next to useless....I have one if you want to buy it $70.......retails for $125

RG

I don't know if I'm right on this, but I think the WB rev box retards the timing, hence the hard starting when cold out problem, retarded timing is what helps on the top end.....whatever they did they can keep it.

I'm still waiting for feed back on the MSD ignition enhancers, ideally the timing should be advanced until the rpm's reach about 5-6 thousand rpm, then gradually retard as the rpm's pick up, and ending up at a max retard value at wot, I doubt very seriuously if the WB rev works like that.

[RED121572]

My 2 cts from my experience with a high rev box.

I also say no. Although, you could get more than just 3 mph out of one. My calculations say an extra 1000 rpms could get you another 7 mph. Anyways......

With that XR Cam, youll never achieve more speed with a rev box. Youll need a much more aggressive cam.

:D

[Ricky g]

I'm wondering if the cdi has a rev limiter function at all, I think all WB did was retard the timing(shortend the spark duration), sure makes sense why the 400 won't start in the cold with a WB rev limiter.......has anybody ever hit the stock rev limiter and felt it stop revving?

RG

[RED121572]

If Im drag racing someone Il hit the rev limiter in first gear. Being almost 30, my reflexes arent as sharp as they were when I was 18, so It takes some more time to react and shift to 2nd gear. :huh :rolleyes: :) :D