You must be talking to norm, because you know very well Joe I'm no expert.
The CDI (Capacitor Discharge IGNITION) 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. So it's ideal for 2-strokes that would otherwise have fouling plugs.
The disadvantage of the CDI is that the spark is very short in duration. So if the mixture doesnt ignite exactly under spark occurrance, it doesnt get a second chance. To ignite, it has to be right. So the trick is to make a longer spark in duration. Now that's what the Answer Roost Boost used to do. Okay the problem : they are for 12V, second they stopped making them 10 years ago.
Now there's a thing called "CDI Mapping" Which is very new to me and I'm still learning about it. But this is what I got so far.
A 2-stroke, actually responds better when you start retarding the ignition above say 2/3's of its normal rpm. So if a 2-stroke runs up to 9000 rpm, you start retarding from 6000 rpm on up and back down. Advancing up to 6, retarding after 6.
4-strokes dont have that, they advance to a certain point and stay there. The modern 4-strokes have different maps for different throttle settings. They have a different advance, maximum advance for full throttle compared to half throttle or a third throttle or 8% throttle.
So you have different maps for different throttle settings. You can change the delivery of power by changing the map.
