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Wiring an aftermarket tach

Started by memper, November 27, 2012, 05:56:18 AM

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memper

November 27, 2012, 05:56:18 AM Last Edit: November 27, 2012, 06:00:15 AM by memper
So I found this cheapy aftermarket digital tach on amazon. I think its from China, we'll see if it can do the job.
Anyways, it has three wires (black, red, green). The green I am assuming is the signal wire. I read in some places that you just wrap the signal wire around the spark plug. Theres gotta be a more elegant way. Can I splice it to one of the leads from a coil?
Next, what really concerns me is that the wires coming from the unit are pretty small. Printed on them its says 24awg/300v/80ËšC (176ËšF). Will this suffice or should I take the unit apart, remove the wires from the board and solder in bigger wires?
"Calling a bikini fairing on a monster a fairing is like calliing a girl in an actual bikini proper work attire....unless shes a stripper." -He Man

-----------------------------------------
Important: always check your battery filter and regularly change your headlight fluid.

ducpainter

#1
November 27, 2012, 11:58:27 AM Last Edit: November 27, 2012, 12:04:17 PM by ducpainter
That wire size will be fine.

Not sure if you can attach the signal wire to the coil.

If your bike is carbed the tach may show double actual rpms as the ignition uses a wasted spark

"Once you accept that a child on the autistic spectrum experiences the world in
 a completely different way than you, you will be open to understand how that
 perspective
    is even more amazing than yours."
    To realize the value of nine  months:
    Ask a mother who gave birth to a stillborn.
"Don't piss off old people The older we get, the less 'Life in Prison' is a deterrent."


memper

#2
November 27, 2012, 03:48:33 PM Last Edit: November 27, 2012, 05:04:41 PM by memper
It is carbed. So is there a way to wire this tach so it reads properly?
Maybe some kind of module that fools the tach into thinking I've got a single fire twin?
"Calling a bikini fairing on a monster a fairing is like calliing a girl in an actual bikini proper work attire....unless shes a stripper." -He Man

-----------------------------------------
Important: always check your battery filter and regularly change your headlight fluid.

ducpainter

#3
November 27, 2012, 05:30:52 PM
Quote from: memper on November 27, 2012, 03:48:33 PM
It is carbed. So is there a way to wire this tach so it reads properly?
Maybe some kind of module that fools the tach into thinking I've got a single fire twin?
Dunno about tach fooling modules.

Any literature with the tach?
"Once you accept that a child on the autistic spectrum experiences the world in
 a completely different way than you, you will be open to understand how that
 perspective
    is even more amazing than yours."
    To realize the value of nine  months:
    Ask a mother who gave birth to a stillborn.
"Don't piss off old people The older we get, the less 'Life in Prison' is a deterrent."


carbmon

#4
November 27, 2012, 06:38:38 PM
All the electronic tachs I've used get their trigger from the primarly coil circuit (the thin low-voltage wire between the ignition module and the coil, NOT the high voltage secondary fat wire from the coil to the plug).  The primary coil circuit (trigger) is only 12v.

Years ago I played with an early electronic tach for a car that used an 'induction' pickup clamped around the secondary (plug) wire - haven't seen one of those in awhile, though.

If you're lucky there's a way to 'program' the tach unit to ignore or multiply pulses to account for different numbers of cylinders / wasted spark.

Came with no instructions or do you need a translator?
2001 M750 Monster - for quick therapy
2004 ZG/GTR1000 Concours - for sale
2012 DL650 Wee Strom - my first fuel injected / ABS bike!
1981 R100RS - long hauler emeritus (retired)
++ with thanks to Daniel Bernoulli, (almost) all my bikes have carbs ++

memper

#5
November 27, 2012, 08:03:53 PM
No switches on the back and no instructions. What can I say, I got what I paid for...
There is actually an adapter for dual fire tachs to hook up to single fire ignitions. I need one for the other way around though.
I guess I will hook it up and see what happens. Who knows, maybe it will work just fine. But my intuition and experience says it aint gonna be that easy.
"Calling a bikini fairing on a monster a fairing is like calliing a girl in an actual bikini proper work attire....unless shes a stripper." -He Man

-----------------------------------------
Important: always check your battery filter and regularly change your headlight fluid.

carbmon

#6
November 27, 2012, 08:24:07 PM Last Edit: November 27, 2012, 10:28:11 PM by carbmon
Quote from: memper on November 27, 2012, 08:03:53 PM
No switches on the back and no instructions. What can I say, I got what I paid for...
There is actually an adapter for dual fire tachs to hook up to single fire ignitions. I need one for the other way around though.
I guess I will hook it up and see what happens. Who knows, maybe it will work just fine. But my intuition and experience says it aint gonna be that easy.

Often the setup/configuration is accessed by a sequence of pushes on the frontside 'mode' buttons if you have any of those.  Maybe some time on Google looking for a similar unit or using names in the Amazon ad would yield some joy.

Not sure which you got but I copied the title from Amazon for this unit into Google and added "instructions" ... came up with this site, maybe gives you some hints on what to try

Click here, than on the “Instructions, media” tab on the webpage

BTW, the linked instructions do in fact describe wrapping the trigger wire around the plug lead, in addition to showing how to set up for different trigger pulses.

HTH and Good luck!
2001 M750 Monster - for quick therapy
2004 ZG/GTR1000 Concours - for sale
2012 DL650 Wee Strom - my first fuel injected / ABS bike!
1981 R100RS - long hauler emeritus (retired)
++ with thanks to Daniel Bernoulli, (almost) all my bikes have carbs ++

ducpainter

#7
November 28, 2012, 03:41:55 AM
I wired my tach to the signal wire at the ignitor box by the battery.

It's programmable though.
"Once you accept that a child on the autistic spectrum experiences the world in
 a completely different way than you, you will be open to understand how that
 perspective
    is even more amazing than yours."
    To realize the value of nine  months:
    Ask a mother who gave birth to a stillborn.
"Don't piss off old people The older we get, the less 'Life in Prison' is a deterrent."


memper

#8
November 28, 2012, 07:38:36 AM
Ok so if this doesn't work then I should be looking for a tach that is dual spark compatible yes?
"Calling a bikini fairing on a monster a fairing is like calliing a girl in an actual bikini proper work attire....unless shes a stripper." -He Man

-----------------------------------------
Important: always check your battery filter and regularly change your headlight fluid.

carbmon

#9
November 28, 2012, 08:07:40 AM
Look for one that can be set for different number of cylinders - use that setting to 'trick' it to give the right reading.
2001 M750 Monster - for quick therapy
2004 ZG/GTR1000 Concours - for sale
2012 DL650 Wee Strom - my first fuel injected / ABS bike!
1981 R100RS - long hauler emeritus (retired)
++ with thanks to Daniel Bernoulli, (almost) all my bikes have carbs ++

ducpainter

#10
November 28, 2012, 12:18:53 PM
Quote from: carbmon on November 28, 2012, 08:07:40 AM
Look for one that can be set for different number of cylinders - use that setting to 'trick' it to give the right reading.
Exactly.

My Spa is set as a twin even though it only reads one cylinder.
"Once you accept that a child on the autistic spectrum experiences the world in
 a completely different way than you, you will be open to understand how that
 perspective
    is even more amazing than yours."
    To realize the value of nine  months:
    Ask a mother who gave birth to a stillborn.
"Don't piss off old people The older we get, the less 'Life in Prison' is a deterrent."


memper

#11
November 28, 2012, 12:29:37 PM
Gotcha. Or a tach for a single cylinder bike... ???
"Calling a bikini fairing on a monster a fairing is like calliing a girl in an actual bikini proper work attire....unless shes a stripper." -He Man

-----------------------------------------
Important: always check your battery filter and regularly change your headlight fluid.

ducpainter

#12
November 28, 2012, 01:52:55 PM
Quote from: memper on November 28, 2012, 12:29:37 PM
Gotcha. Or a tach for a single cylinder bike... ???
A tach for a single with a waste spark or a twin with a single spark.
"Once you accept that a child on the autistic spectrum experiences the world in
 a completely different way than you, you will be open to understand how that
 perspective
    is even more amazing than yours."
    To realize the value of nine  months:
    Ask a mother who gave birth to a stillborn.
"Don't piss off old people The older we get, the less 'Life in Prison' is a deterrent."


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