Tachometer wiring question

[Elimax]

Hi all:

I'm currently installing a Virago tachometer on my Max, and I got no result from wiring directly onto the the signal receiver on the stock tach.

So, my question is this: What should I splice the Virago wire into to receive a strong enough pulse to make it "work"?

(Please note that all the other parts of the tach are working.)

Thanks!

Elimax

 

[gamorg02]

did you check at a multitude of RPM ranges? I tcould be thinking its running 1/2 as slow or something similar. if my math is right the virago is a v2 right? so the vmax is a v4 plus a wasted spark so it fires like a v8? so a virago tach thinks the engine would be running 4x faster? maybe?

also, do you know how the virago tach signal wire works?

 

[Elimax]

Yes, the tach signal wire works. What I'm trying to find out is which wire to splice it into.

Elimax

 

[[email protected]]

oops

 

[gamorg02]

Yes, the tach signal wire works. What I'm trying to find out is which wire to splice it into.

Elimax

it should just splice into the back 3 of the stock tach, unless its set up for the wrong pulse information.

 

[Elimax]

Yup...I tried into the back of the stock tach, but got nothing. So I'm hoping to find a wire/region where the signal is stronger.

Elimax

 

[gamorg02]

its strong enough to run the oem tach and a shift light, i don't think thats the issue man.

 

[dingy]

The tach can be wired to any of the 4 coil trigger wires wires that are NOT the Red with White tracer.

Normally, the tach reads of off #2 coil trigger circuit, which is a gray wire. Inside the wiring harness is a splice to this gray wire which runs from the TCI to #2 coil.

This same circuit also feeds the fuel pump relay & the VBoost unit.

It does not matter which coil the tach is fed from, so using #4 coil (right front) may provide a better signal.

#4 should be a White wire to the trigger side.

And not sure the 85-89 VMax has a wasted spark system, these years have 4 pickup coils so it should be a dedicated fire. The 90-07 with one pickup coil is a wasted spark style.

Gary

 

[MR_NST]

What a fantastic idea... post some pics of the finished product.

evan...

 

[Elimax]

Well, she's up and running now...I wired her into whatever the non-red wire is on coil number 4 (don't rememember the color this late at night!)

It's flippin' FANTASTIC to have an easily visible large tach right in plain view and right next to my Koso digital speedometer.

Thanks for your input...and if anyone wants tips on doing this, lemme know. (Also, a nice side note, I bought the tach from Jon at vmaxbitz for under $100.)

Elimax

 

[gamorg02]

does the aged virago tach look weird compared to the koso?

i'd love to see some pics

 

[gamorg02]

The tach can be wired to any of the 4 coil trigger wires wires that are NOT the Red with White tracer.

Normally, the tach reads of off #2 coil trigger circuit, which is a gray wire. Inside the wiring harness is a splice to this gray wire which runs from the TCI to #2 coil.

This same circuit also feeds the fuel pump relay & the VBoost unit.

It does not matter which coil the tach is fed from, so using #4 coil (right front) may provide a better signal.

#4 should be a White wire to the trigger side.

And not sure the 85-89 VMax has a wasted spark system, these years have 4 pickup coils so it should be a dedicated fire. The 90-07 with one pickup coil is a wasted spark style.

Gary

why was the 4 coil a better signal? isn't deteroirated by running to vboost/fuel pump?

also hadn't heard that about the 85-89 but makes sense, can anyone confirm?

 

[dingy]

why was the 4 coil a better signal? isn't deteroirated by running to vboost/fuel pump?

also hadn't heard that about the 85-89 but makes sense, can anyone confirm?

I am just speculating that the other tie ins to the #2 coil signal may slightly weaken it. He was asking for a better option and that was the one thing that came to mind.

Gary

 

[MR_NST]

so if one was to do this on a 90-07 would it work due to the wasted spark?

Evan...

 

[bazwell]

also hadn't heard that about the 85-89 but makes sense, can anyone confirm?

Can't check/confirm it at the moment, but I'm interested in the answer.

 

[gamorg02]

I am just speculating that the other tie ins to the #2 coil signal may slightly weaken it. He was asking for a better option and that was the one thing that came to mind.

Gary

makes sense to me. i was just wondering, hopefully my question didn't come off ****-ish.

so if one was to do this on a 90-07 would it work due to the wasted spark?

Evan...

good question. it might read 2x fast is all.

 

[dingy]

so if one was to do this on a 90-07 would it work due to the wasted spark?

Evan...

If you are referring to connecting into the #4 coil for the tach pickup the answer is Yes, it will work.

The tach is just looking for a pulse that is provided by the TCI to 'count' number of pulses per minute and then calculate an RPM based upon what it has been programmed. This programming consists of number of pulses per minute divided by either 1 or 2. Divided by one indicates a dedicated spark & divided by 2 indicates a wasted spark, which means that the plug fires on the compression & exhaust stroke. If the tach is an aftermarket tach there will probably be a switch on it to change input modes. If it is a stock tach, it can hook to any one of the 4 coils with no other changes.

If you put a tach from a 85-89 VMax on a 90-07 VMax, it would read 2x the actual RPM's. This is assuming I am right about the 4 pickup coils not being a wasted spark & the single pickup coils being a wasted spark.

The tach doesn't care if it is hooked to any one of the 4 coils trigger wire. NOT the Red/White wire that runs to each tach. Wire colors are normally, #1=Orange, #2=Grey, #3=Yellow, #4=White. This may not be correct in all cases though.

Gary

 

[Miles Long]

If you are referring to connecting into the #4 coil for the tach pickup the answer is Yes, it will work.

The tach is just looking for a pulse that is provided by the TCI to 'count' number of pulses per minute and then calculate an RPM based upon what it has been programmed. This programming consists of number of pulses per minute divided by either 1 or 2. Divided by one indicates a dedicated spark & divided by 2 indicates a wasted spark, which means that the plug fires on the compression & exhaust stroke. If the tach is an aftermarket tach there will probably be a switch on it to change input modes. If it is a stock tach, it can hook to any one of the 4 coils with no other changes.

If you put a tach from a 85-89 VMax on a 90-07 VMax, it would read 2x the actual RPM's. This is assuming I am right about the 4 pickup coils not being a wasted spark & the single pickup coils being a wasted spark.

The tach doesn't care if it is hooked to any one of the 4 coils trigger wire. NOT the Red/White wire that runs to each tach. Wire colors are normally, #1=Orange, #2=Grey, #3=Yellow, #4=White. This may not be correct in all cases though.

Gary

Gary -
I have a spare OEM tach, that I plan to install on my bike before the riding season starts (my present tach has needle wobble issues)
I'm not sure what model year the tach is from, only that the redline is set at 9500, so it must be an early one.
I think the tach may have a switch like you mentioned - there is a little blue square device on the circuit board, with a clockface affair with markings, and a centre plug with a screwdriver slot.
If I find that this tach does not read rpm correctly, I'll try adjusting this "switch" Thanks!

 

[MR_NST]

So there is no specific year of Virago tach required for correct RPM readout its moreso the look and rpm readout. 95+ tach i think? Thank you for this AWESOME input as this will get done to my bike. It would look factory and thats the best part about this mod! thanks.

Evan...

 

[MR_NST]

btw i thought 9500 rpms the change to 9000 was late 90s early 2000s. someone correct me if this is wrong.

evan....