How to assemble a voltage regulator on a Soviet moped?

Question

Electronics

Hello. Restoring a Soviet moped. I want to make LED lighting. I disconnected the generator windings from the ground and rectified the voltage using a diode bridge. But the problem is that the voltage is not stable and at max speed it reaches almost 50 volts without load. At idle without load it is 18 volts. I connected several lamps and the voltage dropped to 9 volts at idle, it swept and all the lamps burned out. Here is the question: please draw a working stabilization scheme in my case. I wanted to try on 7812 chips, but I think it will burn out.

Answer 1

If there is no excitation winding:

Source
If there is a winding (which is unlikely), take the regulator "from shakhi" (VAZ-2106).