I remember following the suggestion of a fellow club member at Halifax as a teenager with an Optima. By judicious use of an 18T 32DP pinion, a 540 motor on a battery pack, and a file, the sprocket teeth were removed from the Optima diff cases. The centres of two Schumacher car belt pulleys carefully enlarged and then glued to the Optima diffs. One Cat belt, and voila, a belt drive Optima
A set of CAT shocks, some home made shock mounts and it was a good racer until I saved up enough to buy the rest of the CAT
Bri