Denny, Obviously you know what you are doing. Help me make more sense out of this. Most mods I have seen on this forum relate to performance exhaust and ear shave mods. One reduces back pressure, one increases air flow. Neither one has a MAJOR effect. No one has increased compression, changed cam profile, bored out the cylinders, or done anything else which would require a drastic increase in fuel flow over the stock requirement. Starting with a base of 132 main jet, I have seen sizes used from 135- 150. I am trying to figure out where or why this much fuel increase is needed. Based on our 750 cc and compression I just don't see where the need is justified.
An engine is basically a self powered air pump,the more air and fuel you can pass thru an engine along with as near as you can get to complete combustion of said fuel mixture,the more power an engine of a given size will make.
The earshave allows a less restrictive intake letting more air into the engine the jets are increased in size to compensate fuel mixture for the added air.
A freer flowing exhaust lets the burned A/F mixture flow out more efficently.
Now, all the fuel and the air in the world is not going to do you any good if it is not burning efficently,this is where the regapping the pickup coils helps. The rotor for the stator has a permanent magnet that turns by the stastionary pickup coils are and when the coils pass through the magnetic field there is a voltage induced into the coils that travels to the ignitor to trigrer it to fire the coils,the ignitor actually turns power on and off the Ignition coils which are basically transformers that take battery voltage and step it up to the higher voltages needed to fire the spark plugs when the ignitor turns of the primary voltace and the magnetic fields collapse and discharge a higher votage from the seconday coils to the plugs.
The pickup coils position in the magnetic field relative to the permanent magnet (closer to the rotor or farther)determines when and how long the ignitor is sending voltage to the ignitor affecting both ignition timing and dwell.
It seems to me that the timing is advanced a small amount and it stays in the field longer when regapped giving a nice fat spark to burn all the fuel and air we are passing through the engine,Iridium plugs also help here too, if for no other reason than they remain at original gap for a long time and the fine electrode seems to help too.
Sorry for bring so lengthy but you asked,I can't believe I typed all that out,shew
I hope it helps you understand why we do the things we do ,a little better.