REV box for stock 400ex..

[ducman998r]

Can anyone tell me the truth on putting a rev box on a 400ex with no engine mods. Im running an FMF full titanium exhaust, K&N air kit w/jets and thats all. I hear the rev boxes only work with a modded engine? True?

[cals400ex]

the rev boxes will not really give you any power. very very small differences if any. the reason they work with built engines is because the aftermarket cams will rev higher. with this happening you will be hitting the stock rev limiter. thus, there is no real reason to get one unless you are hitting the stock rev limiter in normal conditions. and i dont' consider doing burnouts on ice normal conditions.....:blah:

[jsmith2232]

I put one on mine when i got my pipe and K&N and tried swapping for the stock one for giggles and it makes a little difference but with the 416 i have now i tried it again and it definitely makes a difference.