Try our new info resource - "Aladdin's Cave" (Main menu)Just added a separate link to Ash's Dropbox thread (shortcut)
Don't know that bike Graham but from what I can see on a brief look on the Net. I gather that it's a two wire flasher on that model. What's the method of regulation on that bike to prevent overcharging the battery at high revs.? The early twins had a Hitachi unit which incorporated a voltage detector and thyristor 'crowbar' to prevent overcharging (mounted under the battery box) ... bit like the action of zener diode on old 60's Triumphs but a lot more precise. There must be some method of prevention of battery overcharge on that bike and if it's malfunctioning and the flasher has any kind of electronics in it, then the overcurrent charging pulses could cause an erratic flash rate.This is all supposition as I don't know that model. Do you have a circuit diagram? Is it a CD250U. If it was a CD250 'Dream' from '68, I'd be hightailing it down the M1, flashing the cash at you to part with it Ash
the older bikes had windings switched in according to load... eg the headlamp on.
it will go back to the right flashing speed, if you hit the brake or at under 50mph