Dime City Cycles electronic 2.5" tachometer HELP!

surfish95747

Active Member
Hey all, I have a 1996 cb750 that ive been wrnenching on. It is no where near finished, but is at decent stage. Stock, it has an electronic tachometer. It has one wire that goes from the tach to the Ignition control module (see below), color code is Y/G (yellow/green).

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So with the aftermarket Dime City Cycles electronic tach, I connected the green wire (see DDC diagram below)

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to the yellow/green wire that the stock tach used to connect to the ignition control module, instead of connecting it to the negative coil terminal (which I am asuming from the cb750 manual that would be either the L/Y or Y/L wire?

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Anyways, I am not sure how accurate this tach is. I have a really cheap tach somewhere that you wrap the tach wire around a spark plug wire. Should I use that to verify the accuracy of the tach? I question the accuracy because my stock tach says my bike redlines at 9000 RPMs, yet with this tach and how I have been riding it without a tach says I am getting up to 12000 RPMs before shifting. It also says I am idling at around 2000-2500 rpms. Which, when I had the stock tach on it, I think I remember it idling at 1000 to 1500. Anyways, does it look like I have the tach wires connected to the correct harness wires? And how would you guys check the accuracy of the tach? Thanks!
 
The ratio of the tach looks right for your bike, so I'm guessing maybe the signal from the ignition unit is the issue?

Have you tried wiring green wire from the tach to either the yellow or blue wire on one of the ignition coils?
 
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