big gun rev box vs. amr rev box for 400ex

[05honda400ex]

wat would give me the most power gain but not tear up my quad

stay away from the wb box...

The CDI box comes from an XR250 kick start bike. It's equipped with a circuit
designed to help keep the engine from "kicking back" on the rider.

What it essentially does is not fire the spark plug if the engine doesn't crank
above a certain RPM. This preset RPM level is just barely under the normal
crank speed of a 400EX... So, throw in some thick oil & cold temps, or simply
a low battery, and it's just enough to cause the engine not to start.


What it all boils down to is unless you have a highly modified engine with a
wild cam and high compression, the CDI box is not doing anything but taking a
safety net away from your engine & causing it to be difficult to start.

If you have the mods to support it, there are a few engine builders out there
that have figured out how to eliminate the rev-limiter out of the stock CDI,
which avoids using the XR250 CDI and it's anti-kickback circuit.

[05honda400ex]

alright so just stay away from the cdi box (i dont have any engine work done on my quad). is putting a jet kit in a good idea or not

[nakomis0]

I don't know much jets kit work. I mean if your bikes getting the right amount of fuel whats a different size jet or needle shape really gonna do? Its not adding any more air. I guess it might allow you to fune tune the jetting. I would never buy one. Good questions though look how much money your saving just by asking. :)

How about trying a ...
14 tooth sprocket
Exhaust
Cam
Air filter
Lighted flywheel
High compression piston
Remove the airbox lid.

Thats all the cheap stuff I can think of.

you should not really need to re-jet(use a jet kit) unless you change change how much air is flowing through the system...for instance...changing to a higher flowing air filter, changing to a more free flowing exhaust requires jetting changes, as well as does major elevation changes and sometimes weather/season changes...

read this link to understand more:
http://www.jetsrus.com/FAQ_jet_kit.htm

[05honda400ex]

alright well i already have an hmf pipe and a k&n filter. putting a jet in give me ne more power?

[aDviSol2y]

If you have the stock jets in with the pipe and filter than you are starving your bike of fuel. So yes you do need to go up on your jets. And yes it will give your bike some more power. There are lots of threads on here about jetting. Use the search and read them. You should be able to find out what you need.

[05honda400ex]

ok thanks for everything