over rev boxes

[ida400ex]

i have a stock 400EX am putting an exhaust and a air filter on it. i was woundering if a over rev box would be wise investment or if it would just ruin and burn up my my bike.

[xben719]

All I can tell you is my two cents. I don't think that they are worth it. I mean in all honesty how often do you hit the stock rev limiter. I also heard that they are not good on your electronics. I mean if you really need another 1000rpms than go for it i guess.

[04exking]

I thought that it really helped my ex get up. But thats just my two cents. lol

[lpmaster]

it wont burn up your bike, but its also not worth it on a stock motor, you'll still be making the same power at the same rpms, maybe with a slightly different ignition curve....but it wont help you

rev boxes are for motors(highly worked) that can make useable hp past the stock rpm limit

[Kaleigh]

its fine to put it on a stock motor.. and you will feel the difference.. i think the motor runs a little better since it does change the curve a little bit.. i put my machine back to stock form and put my stock cdi on.. it was ok.. but then i put my new cdi in and its alot better.. the machine revs better and seems to run smoother..

i had one...i killed 2 batteries trying to start the bike before i was told to put the stocker back in...

essentially they are a stock cdi off of a dirt bike. there is a circuit in them that prevents the spark plug from firing if the rpms do not reach a certain point. this is to prevent kickback. that rpm level(for argument sake only, not sure if it is the actual rpm level) is, we'll say 1400 rpm. the 400ex starts at say, 1500 rom. if the rpms don't get up ove rthat 1400, then the plug don't fire and the bike don't start. you will need to have a 110% charged battery all the time and hope that the temperature isn't low enough to cause the motor to turn slow...

[vze2hnvz]

Many of the aftermarket boxes for the 400ex are actually just the stock cdi off a Honda XR250R with a different label - gives you about 900 more rpm's and a bit faster ignition curve.

[jordan_m6]

Originally posted by lpmaster
it wont burn up your bike, but its also not worth it on a stock motor, you'll still be making the same power at the same rpms, maybe with a slightly different ignition curve....but it wont help you

rev boxes are for motors(highly worked) that can make useable hp past the stock rpm limit

Test have been done to prove you wrong. You will notice the rev box more on a basicly stock motor vs a built motor. Due to the fact that you have already upgraded the performance far enough to where the small amount of enhancement will not be noticable, where as if you have a stock motor it will be more noticable cause of fewer mods and less power.