This is a photograph of the Cmos 4011 based Motorcycle Alarm No.3
. The circuit features an intermittent siren output and automatic reset. It can be operated manually using a key-switch or a hidden switch - but it can also be wired to set itself automatically when you turn-off the ignition. By adding external relays you can immobilize the bike - flash the lights etc. It's easily adapted for a 6-volt system - so it will protect your "Classic Bike". And the standby current is virtually zero - so it won't drain your battery.