You need to get a bulb 12 with two wires. You will also need the tester. As a depth gauge you can use a Vernier caliper. The gap is easiest to measure with a feeler gauge.
To start, Unscrew the cap of the generator. Also, you can remove the right crankcase cover. So it will be much easier to work on. Clockwise rotate the crankshaft. Turning do for the generator bolt. You must achieve the maximum opening of the breaker contacts. Then loosen the screw and turn the eccentric. Between the contacts there should be a clearance of 0.4 - 0.6 mm. tighten the screw.
Then rotate the crankshaft clockwise. The piston must be set at top dead center. Then rotate the crankshaft counterclockwise. The piston must reach the TDC about 3.0 - 3.5 mm. Loosen the screws and set the beginning of a contact opening. Secure the screws. The opening contacts is easiest to determine using a probe. One wire connect to ground and the second terminal of hammer breaker. Turn on the ignition. Should turn on a lamp when opened.
If you have БС3, it is necessary to exclude the item installation gap. The time you will need to identify the tester. Set it to measure voltage. Connect it to the second and third contact HH. The tester should show voltage of about 7 volts at the time when the modulator is not in the HH. When the modulator will be in DH, the voltage should change from 7 to 0. At the moment, and there is a spark.
For each cylinder set ignition separately. It is recommended to start with the Adjuster on the left breaker. After installing the spark can jump to the right breaker.