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Author Topic: Electric Tach  (Read 1332 times)

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Offline AHawks

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Electric Tach
« on: June 11, 2011, 02:26:54 PM »
Ok I need some help. I have a electric car tach and the stock points ignition on a cb550k1. Is there a way to hook this up? I have no problem making an adapter, but none of the adapter schematics online seem to work. Thanks in advance.
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Offline dave500

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Re: Electric Tach
« Reply #1 on: June 11, 2011, 03:13:12 PM »
has it got switches on the rear?single cylinder/two stroke might work.
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Offline AHawks

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Re: Electric Tach
« Reply #2 on: June 11, 2011, 04:09:57 PM »
No just a 4-6-8 switch.
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Offline CycleRanger

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Re: Electric Tach
« Reply #3 on: June 11, 2011, 10:17:35 PM »
Apparently it can work but it must be connected to both coils with some resistors.

There's a lively discussion here:  http://www.venturerider.org/forum/showthread.php?t=29859
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Offline AHawks

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Re: Electric Tach
« Reply #4 on: June 12, 2011, 06:06:35 AM »
Yeah I found that and it didn't work at all. I made a adapter using another suggestion and it will read up to 2000 rpm but anything above that and the needle drops back to zero.
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Offline skamagedon

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Re: Electric Tach
« Reply #5 on: June 12, 2011, 07:57:40 AM »
you would need a pulse width modulator to double the signal from the coil
 because of the negative spark
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Offline Triffecpa

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Re: Electric Tach
« Reply #6 on: June 13, 2011, 06:19:19 PM »


I use a Summit Automotive tach on my CB400F race bike.  I set it to "Four Cylinder" mode.  The bike runs a Dyna S ignition and one of the Dyna diode adapter things to pull a signall off both coils.  Works like a charm.

Don't have specific input on a points system, but it really shouldn't matter.  The points and the Dyna S essentially do the same thing.

Are you sure that the tach works properly?

Tracy


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Offline AHawks

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Re: Electric Tach
« Reply #7 on: June 13, 2011, 06:52:14 PM »
Yeah tach works great off one coil. Read exactly half. I have tried every combination of diode/resistor adapters I have found online. I just want to make sure I am using the right diodes. I am using 30A surge. Type is 1N4005. Peak Inverse Voltage (PV) is 600.
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Offline Triffecpa

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Re: Electric Tach
« Reply #8 on: June 13, 2011, 07:31:01 PM »
Quote from: AHawks on June 13, 2011, 06:52:14 PM
Yeah tach works great off one coil. Read exactly half. I have tried every combination of diode/resistor adapters I have found online. I just want to make sure I am using the right diodes. I am using 30A surge. Type is 1N4005. Peak Inverse Voltage (PV) is 600.

don't have any idea what is inside the black tape on the unit that I got from Dyna.  They sell them for $15 or $20 or something.

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