Agree with all that's been said - not the regulator I would think, as the flicker is there with some ammeters always (and the old mechanical regulator works at a rate of knots that would confound any needle!). I've just put a 2 inch white-faced Miller one on the A10 (no prob for me as the h/lamp shell isn't the original type and so I didn't mind enlarging the 'ole). These instruments, which ain't cheap, are the best I have had. I forget quite what the operating mechanism is (moving magnets?), but not the same as the cheapo pattern things, and very well damped and accurate. I have 2 of these on 2 bikes one is 12-0-12A, t'other 15-0-15A. On 2 other bikes I have original Lucas ones - and they are pretty OK with mechanical or electronic regulators at 6 or 12v. On another bike I have a replica thingy which flutters like a tart's eyelids and whose needle is poorly mounted/damped. Looks smart but isn't great, although you can tell whether it's charging or not most of the time. I've had that on twins and a single and it's as bad on either (currently on a single). If I'm ever in doubt as to whether things are charging or not, I just put the rear brake on and watch the ammeter needle surge in the charge zone as the dynamo (or alternator) meets the extra demand. But if I want one that works nicely, I've decided the big Millers are the best thing and also the easiest to read where 'original' isn't a big issue.
