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Cable to electronic tachometer conversion

3767 Views 5 Replies 5 Participants Last post by  DannoXYZ
Hello all,

My tachometer does not function on my 1978 Suzuki GS550. It came with a spare, which works, but it's from a different model and doesn't fit in the housing lol. Since the original gauges are gigantic, this is a good opportunity to clean up the head with a smaller gauge(s). Both the speedo and tach run on cables and it is not easy finding aftermarket gauges which are not wired/electronic. In fact, I haven't found a single aftermarket tach on eBay which is not electronic! I've looked on youtube for help converting, but their success is pretty spotty.

Has anyone here actually successfully converted their cable tachometer to an electronic gauge? Can you share which gauge you used and how you wired it?

Thanks!!!
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I've done several and it's a fairly common job on Harley's that are being customized. The usual brand is Dakota Digital but they are expensive. I'm sure there are other brands out there but off hand I can't think of any names.

The usual method is to run the electronic tach off of the ignition circuit that operates the coils. Every time the coil fires on a single cylinder engine with a single fire ignition, for example, that's 2 revolutions of the engine, and the unit itself will convert that to RPM. The trick will be finding a unit that is set up for your bike's ignition, or can be set up for it.

You might want to call JP Cycles metric tech line and see if they can suggest a unit that would work on your bike.
Thanks!!!! I had no idea that JP had a help/tech line!
Thanks!!!! I had no idea that JP had a help/tech line!
Any word on whether or not this worked? Facing the same problem 5 years later!
Any word on whether or not this worked? Facing the same problem 5 years later!
A 5 year old post from the OP may not get a reply. You might consider opening a new post with your problem.
Aftermarket tachs usually have multiple options for sensing trigger-signal:

  • connect to factory ignitor (neg-trigger). This is best and cleanest option
  • connect to coil spark-output (high-volt trigger), not as clean, but can work
  • inductive pickup around plug-wire, least reliable

Consult manual for your aftermarket tach to see how to configure it for various trigger inputs. A pull-up resistor may need to be used on trigger wire, depending upon type of signal you're tapping into.
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