Measuring RPM

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Nov 25, 2015 | 05:47 AM

3twinridges

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Measuring RPM

I am guessing the best way/only way to measure RPM on a flathead with no tachometer is to use an inductive meter. Does anyone have any recommendations for a test meter that works well on 6v positive ground? The one I picked up at Harbor Freight isn't cutting the mustard. Trying to dial in my carb to spec.

JB

Nov 25, 2015 | 08:22 AM

3twinridges

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Cargo Master

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Or, has anyone had a good experience with a timing light thAt has a tachometer built in (reflective tape) and works on 6v current?

Nov 25, 2015 | 08:46 AM

CBeav

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From: Louisville

You don't have to look for a 6v light, just hook a 12v timing light to a 12v battery and place the pickup on a plug wire. Also available are hand-held photo tachs, ~$12 and up. Cheaper = need to be closer to target, hard to do with a fan spinning close by so make your mark on a fan blade (providing the fan pulley is the same diameter as the crank pulley.) Trying to be on spec is fine but really not critical with old, non-automatic trans vehicles.