I spent 2 hours searching thew web trying to find a way to obtain full revs/power from each gear but couldn't find a definitive answer.
This is for bikes with the 3 pin cdi connector along with the 4 pin connector, and fitted with the rotary gearbox switch.
- You need to inline solder a 1.5k ohm resistor (50p Maplin) on the green/yellow wire.
- Then cut the green/yellow wire from the gearbox switch end and connect that to Earth.
The green/yellow wire then has a constant 1.5k ohm resistance to earth in all gears, and therefore max power in all gears.
Hope that helps!

Don't cut any wires, no need!
Just disconnect at the bullet connection then splice the resistor between the CDI end and the frame, simply leave the gear sensor end loose as its no longer used.
The cdi now only see's the resistor and thinks the bike is always in a low unrestricted gear.