The ignition pickups are located on a moveable plate under the left sidecover. The plate has graduated lines on it, each being ~2 degrees. Simply loosen the nuts on the plate, move to the desired setting, and tighten. The air gap should be .6-.8mm.
Soon I will start work on a programmable CDI for the carbed 2v's. Then none of this plate-moving stuff will have to be done, you can change timing from a laptop. It will have a shift light, shift kill, available TPS input, and adjustable rev limiter, all built in. It will probably be a couple months until it is done, however.