Mac was then road legal but...
The 1.5BHP engine struggled to pull up the hills around here, that was fixed by some port tunning.
The inlet, transfer and exhaust ports in the cylinder were opened up to AV89 specifications, that allowed the gasses
to move around the engine a lot easier.
Next was a high compression cylinder head, this brought the engine up to full AV89 spec, what difference does that make,
well the power increases to 2.5BHP, and with a 15mm carburetor fitted this makes for a much better, faster, ride.
I also fitted a pull start which allowed me to remove the pedals and give Mac that lean appearance.
On the other side I fitted a pretty new pulley wheel with a changeable sprocket.
It looks good and I can, if I need, alter the final drive gearing.
The end result is a nippy little run around that is fun to ride.