[Country Boy]

ok. this sounds stupid. but its bugging me. i know the CDI box is up front beneath the hood on my 400ex. and there is the regulator in the back by the air box. What does that do??? and whats the difference between the two??? Red, :hail:you should be able to help me on this one. you know your stuff.

 

[mud99]

The one under the hood is the ICM Thats what my Honda manual says.

 

[Helmut]

CDI is your ignition. It takes the place of breaker points like were used in older ignition systems, except it's solid state and has no moving parts.

Regulator is the regulator/rectifier. It converts the AC power that your stator coils puts out to DC power and it also regulates the voltage to keep the battery from overcharging. It will be the one with the cooling fins on it.

 

[Redracer]

The regulator rectifier is a combined unit. It does the rectifying part as well the regulation part. It is part of a battery charging system. It gets a power feed, an AC power feed from the stator. Most of these regulator rectifiers and Stators are 3-Phase, for charging batteries, so there are three wires coming from the stator feeding into the regulator rectifier. Then the regulator rectifier rectifies it, and regulates the power to 14.5 volts and feeds a DC out to the battery. There are some single phase, regulator rectifiers as well that basically do the same thing. You have two wires coming from the stator, feeding into the regulator rectifier which is then connected up to the battery, so there is a DC output going to the battery.

A CDI is short for Capacitor Discharge Ignition. A CDI is an electronic ignition that uses a capacitor to store energy to which then gets discharged through the ignition coil. The advantage of a CDI is that the spark energy is very high, you get a very powerful spark, and very high voltage.

 

[69quadracer]

Bravo, very well said Professor Redracer!!

 

[Redracer]

You're making me blush...

 

[Country Boy]

So which one would i chance to get higher rpms??? the CDI?

 

[Helmut]

Yeah, aftermarket CDI will do away with rev limiter and change your timing curve.

 

[TRX2fiveO]

The CDI you willl roughly gain about a grand on RPMs usually? right professor RED!!

 

[tomgodd]

Great info Helmut and Redracer!!!
Thumbs up to you both!!!!!!!!!!!!!!

 

[Redracer]

You are correct. An aftermarket CDI will give you an extra 1000 RPM.

 

[mud99]

Will that help even with a stock cam or only on a performance cam.

 

[Redracer]

Well the extra 1000 RPMs at the top of 5th gear will give you an extra mph or 2 and the advanced ignition curve helps throttle response. But to get the full effects of the new CDI a more aggressive cam is required.

 

[mud99]

I thought about getting a cam out of a XR400 and new headgasket for the 400EX for a little extra power.

 

[TRX2fiveO]

ill take your carb....