Is it possible to test a Rev Counter?

[Mrlanks]

I’ve been going through some old parts and found this Rev counter/Tacho far bigger than the others in the box which are for motorbikes (I’m into Nortons). Showed it to my dad who thought it was a Jaguar (he had a V12 Coupe E Type), I found a very informative thread on the gauge numbers and see that it is likely to be a early 1960’s version. It was wrapped in newspaper and cosmetically in pretty good shape. Is it possible to test it somehow please?

It’s a bit big for my bikes and as much as I’d like a E type I don’t have one (yet!) so I would be selling it. I haven’t been able to find one with the exact same number so if it is ok to have some advice on a fair value that would be a great help also.

RV 7403/02
Clock CE1111/01

Many Thanks

[mgcjag]

..one here same number https://www.ebay.co.uk/itm/387286957227 ... media=COPY

[Tommd]

It appears the tachometer you have is the early unit that uses a tach generator driven off the back of the intake camshaft. It reads AC voltage. You can test it by connecting an AC voltage source to it. It should read 200 times the voltage. You could use a low voltage transformer such as a train transformer. 10 vac should read 2000 rpm’s. 15vac should read 3000 rpm’s.
Tom