The original 125 engine made about 15bhp at about 10,000rpm with at 6 speed box...the Zongshen 230 makes about 18bhp @ 7000rpm, with peak torque @ 5500rpm with a 5 speed box.
The original gearing was 15/51...which was far too low, so I went to 17/38 (max) which gives me 60mph @ 5500 and the last fuel check I did was 95mpg with an 11L tank.
Zongshen recommend a 30mm carb, but that's far too big IMO, so I settled on a 26mm Mikuni copy and it fuels well.
I had to change from ECU to CDI for ignition and 3 phase to 2 for charging and move the battery and electronics into the airbox, simplifying things as I went along, giving me a few wires left over...LOL.
Dave.
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