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Discussion Starter · #1 ·
Hi!

I want to install a tachometer on my SLR 650. I acquired a RD04 Africa twin tachometer. I have signal from the ignition coil, but it doesn't work, the gauge just doesn't move.
Is it possible that the RD04 tacho just not compatible with the SLR, or should I get signal from the cdi? Thanks in advance!
 

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2003 Honda XL650V Transalp
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The signal you want is the low voltage side of the coil, the CDI output. The gauge also needs a return circuit so you'll need to connect the other side of the tacho to ther frame of your bike. Electricity is a flow of electrons if you don't have 2 wires connected across the source you don't get a reading on the gauge.
[edit]I've had a look at the Africa Twin schematics and all models prior to 1996 have 3 connections a switched positive, a negative and a feed from the CDI. From 1996 onwards there are only 2 wires to the tacho, a negative ground wire and a CDI output wire. I hope that helps.
 

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Discussion Starter · #3 ·
The signal you want is the low voltage side of the coil, the CDI output. The gauge also needs a return circuit so you'll need to connect the other side of the tacho to ther frame of your bike. Electricity is a flow of electrons if you don't have 2 wires connected across the source you don't get a reading on the gauge.
[edit]I've had a look at the Africa Twin schematics and all models prior to 1996 have 3 connections a switched positive, a negative and a feed from the CDI. From 1996 onwards there are only 2 wires to the tacho, a negative ground wire and a CDI output wire. I hope that helps.
Yes, I got 3 connections, the positive and negative is clear, but I'm not sure of the CDI feed. In the workshop manual I saw that there's a ignition pulse signal, that's what I need?
 

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The signal to the tacho is the same as the low voltage input to one of the coils. Right front or right rear depending on the model, but any coil input should work.
I recently converted my '77 Kawasaki Z750B twin from mechanical driven tacho to electronic, just by tapping into the low voltage signal for the coil from the electronic points replacement set up.
 
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