Rev counter interchangeability?

[SteveW]

Can I use the Rev counter of my 1974 550 on my 1980 650?

My 650 one is seized and was wondering if I could use the 550 one temporarily to set the carbs up.

Thanks

[Bryanj]

I think the 650 has a different ratio to all the others

[SteveW]

Thanks Bryan, I’ll have to try and fix my one then.

[Lobo]

A slight long shot, but there are strobe APPs  (using your smart phone camera) that can be used to determine RPM. My guess is it’d need 4 hands, ie you might have to talk nicely to the missus?

[Johnny4428]

A slight long shot, but there are strobe APPs  (using your smart phone camera) that can be used to determine RPM. My guess it it’d need 4 hands, ie you might have to talk nicely to the missus?

That is interesting! worth a shot!

[Bryanj]

Is that the large diameter tacho?

[SteveW]

Is that the large diameter tacho?

Yes, its identical in size to my 74 550 one.

[SteveW]

A slight long shot, but there are strobe APPs  (using your smart phone camera) that can be used to determine RPM. My guess is it’d need 4 hands, ie you might have to talk nicely to the missus?

Might be worth a try, thanks. I do have an oscilloscope attachment for my laptop, I could try hooking that up to the ignition circuit.

[Bryanj]

Dont think i got any large ones but will look next time i find the box.