Jones/Motorola/Moroso tachometer question

[Truckedup]

If you are holding one of these mechanical tachs in you hand with the drive end facing you...Is the correct rotation clockwise or counter clockwise ? I don't have one but am considering adapting it to a motorcycle...

[bill jones]

I google this: jones motorola tachometer rotation direction

-and found this: https://www.pegasusautoracing.com/pdfs/038.pdf
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-looks like they are bi-directional---work either direction.

[Truckedup]

Thanks, I Googled the same words before asking...I missed it...

[bill jones]

-I happen to have one of those old mechanical tachometers mounted on a motor drive unit that I built for spinning Hilborn type fuel pumps.

-this is set up with a reversible motor---haven't used it for a quite a while but I checked it this morning and the tach reads either direction for sure.

[Truckedup]

My vintage Triumph race bike has vibrated the needle off the electric tach. Normally they use Smith mechanical tachs that the passage of time has made them inaccurate or an expensive rebuild and they still are suspect. I see Motorola/Jones/Moroso tachs for reasonable money.I'm assuming they are durable units made for severe service.I have 4-1 Triumph tach drive gearboxes, some Jones tachometers are 4-1....Shouldn't be too difficult to mate up the Jones to the Smiths motorcycle drive...

[kirkwoodken]

Typically, the Jones tach has a flyball mechanism.Spring loaded balls fly out on the mechanism and cause the needle to move. Either rotational direction will give the same readings.