After Market Tachometer

[dllewis5]

Hey everyone,

Was wondering if someone could tell me which wire to tap my digital tachometer into, to make it functional?



This is the tachometer I bought it has a red, black and green wire coming from it. I know what to do with the red and black, but the green wire I'm not sure which wire to splice it to.

My bike is a 1980 CB750c

Thanks,

[icerigger]

The green wire is ground, the red wire to a 12v source and the black goes to the trigger source, usually the primary on one coil. Remember that these bikes use a "wasted" spark so the tach will likely need to be configured for 2 cylinders.

YMMV

[shinyribs]

I've had zero luck with electronic tachs on either the sohc or the sohc. I've had three and none of them ever functioned right. If hooked to the low voltage coil trigger wire the needle would jump erratically. If hooked to a high tension wire ( as many call for, all 3 of mine included)  it would always short out that wire and I'd lose spark on that cylinder.

I wish you luck! If you make it work please report back with your secrets. :D