Device for adjusting ignition timing in a motor-cycle provided with fluid coupling

Claim 1

In a device for adjusting ignition timing for an engine mounted on a motor-cycle which includes an engine; an ignition circuit having at the primary side thereof a thyrister as a switching means, a diode, a capacitor, a primary ignition winding and a rotor of a.c. electric power generator, and at the secondary side thereof a secondary ignition coil and ignition plugs; a fluid coupling connected to said engine; a power transmission mechanism which receives driving force from said fluid coupling and has at least two-stage speed changing function of a low speed drive and a high speed drive; and shift indicating switch means which changes over in association with shifting of said power transmission mechanism to indicate the shift position of the low speed drive, the high speed drive, or the neutral position, the improvement comprising first, second and third ignition signal emitters in said ignition circuit arranged in parallel relative to the gate of said thyrister and to produce output signals by rotation of said rotor of said a.c. electric power generator, the output signal being forwarded to the gate of said thyrister to connect and disconnect the same, said first ignition signal emitter forwarding its output signal to the gate of said thyrister when the shift mechanism is shifted to the low speed drive range or high speed drive range, said second ignition signal emitter forwarding its output signal to the gate of said thyrister when the shift mechanism is shifted to the neutral position, and said third ignition signal emitter forwarding its output signal to the gate of said thyrister when the shift mechanism is shifted to the low speed drive range or high speed drive range and the motor-cycle is in the state of running, said first ignition signal emitter being advanced from said second ignition signal emitter, and said third ignition signal emitter being advanced from said first ignition signal emitter when the motor-cycle is running; and another thyrister for short-circuiting said ignition signal emitters, which is provided in parallel with said first ignition signal emitter, the gate of said thyrister being connected to said shift indicating switch means, and said thyrister being made conductive when said shift indicating switch means has been changed over to the neutral position so that the advanced signal emitter may be short-circuited.