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Author Topic: CB750K - Connecting Digital Tach Cable to Dyna Coils  (Read 230 times)

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Offline Yoshimitsuu

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CB750K - Connecting Digital Tach Cable to Dyna Coils
« on: November 06, 2018, 04:47:33 pm »
Hey all,

I have a quick question about connecting my Daytona Velona 80 Tach/Speedo on my bike. In the wiring diagram, it says to connect the tach wire to the positive on the coils. I just installed Dyna 3 ohm coils and as far as I can tell from what I have read there is no dedicated positive and negative terminals. With that said, where would I connect this yellow wire? I’ll attach the pdf from Daytona below. Thanks in advance.

Offline HondaMan

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Re: CB750K - Connecting Digital Tach Cable to Dyna Coils
« Reply #1 on: November 06, 2018, 05:50:59 pm »
Hey all,

I have a quick question about connecting my Daytona Velona 80 Tach/Speedo on my bike. In the wiring diagram, it says to connect the tach wire to the positive on the coils. I just installed Dyna 3 ohm coils and as far as I can tell from what I have read there is no dedicated positive and negative terminals. With that said, where would I connect this yellow wire? I’ll attach the pdf from Daytona below. Thanks in advance.

Normally the tachs are driven at the (-) wire of the coil, in bikes and cars. But since this one shows it being used either with the cam sensor or with wraps of wire around the spark lead, it is likely a low-voltage signal instead of the higher spike of the points-side of these coils. In any case, connecting it to the Black/White wire (either one) at the coils won't damage it.
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Offline shads

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Re: CB750K - Connecting Digital Tach Cable to Dyna Coils
« Reply #2 on: November 07, 2018, 01:18:27 pm »
Ive got the same gauge and was also confused about the wiring regarding which side of the coils it connects too.  I was informed that it should be connecting to the points side of the coils as the other side is just +12V.

Offline Yoshimitsuu

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Re: CB750K - Connecting Digital Tach Cable to Dyna Coils
« Reply #3 on: November 08, 2018, 02:12:49 pm »
Ive got the same gauge and was also confused about the wiring regarding which side of the coils it connects too.  I was informed that it should be connecting to the points side of the coils as the other side is just +12V.

I'll be checking on this tonight as I just installed the coils and have to cut down the new spark plug wires. I'll report back!

Offline Yoshimitsuu

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Re: CB750K - Connecting Digital Tach Cable to Dyna Coils
« Reply #4 on: November 14, 2018, 06:49:41 am »
I just wanted to report back after my trial and error with this gauge and the installation of the new coils. After days of almost losing parts in the engine and major head scratches I have everything together (for now). I had coil problems and I don't really know why the engine wasn't firing but the splice connector from the Dyna S that was installed by the prior owner was suspect so I just made a solid solder connection and wrapped it.

The instructions for the Daytona Velona 80 state that it should be connected to the positive cable which I thought was the BLK/WHT but it wouldn't work so I connected it to the BLUE cable and it works that way (and I am sure connecting to the YELLOW would yield similar results). The tachometer has to be calibrated though and I found that the 1P - 1R (One Pulse per 1 Revolution) yielded the most accurate reading. I haven't set the speedometer calibration yet as I haven't taken the bike on the road but I will report back when I figure that out too for reference. It really is a nice gauge and I think it looks very clean on the bike.

Offline calj737

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Re: CB750K - Connecting Digital Tach Cable to Dyna Coils
« Reply #5 on: November 14, 2018, 06:55:56 am »
If the gauge uses a sensor to measure ground speed, you should be able to calculate fairly closely the ratio based upon tire size. That gets you close. Once there, you can tweak if you have a vehicle pacing you locked into Cruise control at 40, 50 and 60 MPHs making fine adjustments on the diameter calibration.
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Offline Bodi

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Re: CB750K - Connecting Digital Tach Cable to Dyna Coils
« Reply #6 on: November 15, 2018, 05:25:16 am »
Odd to tell you to connect to coil + since that is just battery power on basically every ignition system using points or equivalent electronic ignition. You need the switched side... the wire to the points.
The speedo is pretty easy to calibrate, you can get a free GPS app for almost any smartphone, it will show very accurate straight line speed.

 

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