Question about sensor wire for tach

[YellowJacket!]

My electronic gauges have two ways of sensing the signal for the tach to work.  The less accurate way is to wrap the sensor wire around the front cyl plug wore - which I have done.  It works but only intermittently.  The preferred method is to wire directly into the tach sensor.
My problem is that the wiring diagram thats posted on the site is for the 83 and the colors are slightly different.  On the back of my old gauges, the wores going to the tach were brown, black and orange.  I think the sensor wire is the orange one but I'm not sure.
So, before I fubar my nice electronig gauges, is the correct tach sending wire the orange or brown one?

Thanks,

David

[The Prophet of Doom]

Ignore what I said it appears to be wrong.  I always had trouble reading those things - so suggest you follow this link to a replica of the diagram
http://rsimonnz.googlepages.com/uswiring82.JPG

[h2olawyer]

Yellow / Black is the rev limiter circuit.  The tach sensor runs from one coil to the tach - on one year it is the grey wire, the other year it is orange (US RJ/RK models).  Don't remember offhand which year is which.  The Haynes manual's diagram says both years are grey.  I'm fairly sure that's not right.  But if there's a grey wire coming from your wiring harness to the plug that (used to) connect to the gauge cluster, that's the one to use.  If it's orange, then use that one.  They won't both be headed there from the coils & there doesn't appear to be any other similar colors heading into the cluster.

Hopefully, someone has one sort of apart & can look at the connectors going into the gauges & can say for sure.  I accept no responsibility for erroneous information in this instance.  I merely consulted the Haynes manual.

H₂O

[treedragon]

If you do have the same gauges as me (Yamaduc post comment), a Vapor, then I might be able to help.

I initially had great difficulty getting a reliable signal from all the recommended ways including TCI wire wraps etc etc. It was recommended I get a resistor to put in the circuit, didn't work in my case but then I discovered that jamming it into the plug to my right ignition coil gave me a perfect signal, gets a bit vague on it when it's raining hard but hey I'm watching the road then not the tach.

I can check tomorrow (it's night here), which one I stuck it in if you like.

[Lucky]

Actually H2O, the speed sensor wire is green with a yellow stripe & runs from the guages to the flasher canceling unit.

the orange wire on one coil, & the grey on the other are the coil primary grounds which run to the TCI. the TCI interupts the grounds to cause the coil field to collapse & fire the coil.  the yellow/black wire runs to the tach, not the speedo sensor & runs the rev limiter

the speedo sensor itself is a small blue cylindrical thing under the speedo magnet.

--Lucky

[h2olawyer]

I don't remember mentioning anything about a speed sensor.  Only the rev limiter & the tach sensor (pickup) wires.  That speed  sensor is part of the turn signal cancelling circuit, isn't it?  I'm pretty sure I disconnected my rev limiter @ the tach end & it was the black / yellow wire.

I was going from what I saw in the Haynes manual wiring diagram which shows both years as having the grey wire running from one coil to the tach.  If that diagram is wrong, then so be it.

H₂O

[YellowJacket!]

I guess what I am looking for is the wire that sends the signal to the tach to give the RPM reading.  From the best I can tell, on the 82 Vision, it is the orange wire.

David

[Night Vision]

according to leather:

The Tach has 4 wires connected to it:
BROWN = +12 volt Power,
BLACK = -12 volts Ground,

GRAY = Ignition pulse signal that the tach reads. It is a "tap" off the Gray wire from the TCI to the REAR cylinder coil. That splice is under the gas tank.
** That's why if you lose the rear cylinder ignition you lose the TACH. **

YELLOW/BLACK stripped wire =This is the Rev-Limit connection.



looking at his picture....



Dave, your "orange" wire is probably the brown wire Leather refers to?
I would wager you want the gray wire between the blk\yl and the blk

[Lucky]

sorry H2O, i think we crossed wires :>

The yellow and black wire sends the TACH info (from the tach board) to the TCI for the rev limiter, not the SPEED SENSOR

SPEED SENSOR is a white/green wire. (earlier i said green/yellow, my mistake)

Orange or Grey wire RUN (to)THE COILS and should not be used unless the instructions SPECIFICLY state to use a coil PRIMARY (12Ga) wire.  (Not the plug wire)

The speed sensor is simply a magnetic pick up like the wire on your fork, Dave.  if you hook 12V to that, you may blow your guage...

[Lucky]

I really should learn to pay attention to what i read.

all this time i'm talking Speedo, Dave's talking tach...
Doh!! :"

oops, nevermind :)

Orange on '82, Grey on '83

[YellowJacket!]

Nightvision, thanks for the picture.  the orange wire that I'm referring to is the top right of the picture.  orange is at about 1 o'clock, black at 3 and light brown at about 5. the rev limiter wire yellow/black is at about 9 o'clock.  After talking to Lucky, I think either the rev limiter wire or the orange one is the one I need to hook into.  I'll check the voltages before I hook up to my gauges.

Thanks for the help guys.

David

[h2olawyer]

That's OK, Lucky - We all misread things from time to time.   ;D

After giving this a little thought, since the rev limiter wire is a tach signal to the TCI, it might work as the signal for your digital gauge, David.  Not totally sure if there's some circuitry in the tach that just makes it an on/off switch @ 12500 RPMs or if that is done in the TCI.  My bet is it's in the TCI, but you might want to make sure.  Since the rev limiter is normally disconnected at the TCI, (mine's unhooked @ the tach), you have a ready wire to use for the digital tach hookup.  Slick, clean & lean - just what one waants for wiring accessories or changes.

Just something to ponder & let folks add their thoughts on.

H₂O

[YellowJacket!]

OK.  Figured it out today and finally finished the job.  I now have a fully functional tach.

On the gauge side of the wiring harness, its the orange wire.  On the wiring harness, its the gray wire.  When I put the two plugs together, the gray and orange wires line up.  I tapped into the gray wire and fired her up and Voila!  I have a nice steady tach.  WOW... YJ is idling at 850.  :D

David

[QBS]

Correct idle rpm is 1100.

[Extent]

The rev cut circuit is in a daughter board in the tach, all the frequency counting happens in the guages so the yel/blk wire will only be grounded on cut, and doesn't carry any rpm info. 

If you want to remove all of the rev limiter electronics you can just cut the three jumper wires between the two boards (two are power, one is tach signal) on the Tach and unscrew the board from the mount.  Hey, weight savings right? :p

I left the rev-cut wire intact, just incase a more reliable rev limit circuit comes out.

[YellowJacket!]

Correct idle rpm is 1100.

Adjusted it. now between 1050 and 1100.

David

[undertaker]

OK.  Figured it out today and finally finished the job.  I now have a fully functional tach.

On the gauge side of the wiring harness, its the orange wire.  On the wiring harness, its the gray wire.  When I put the two plugs together, the gray and orange wires line up.  I tapped into the gray wire and fired her up and Voila!  I have a nice steady tach.  WOW... YJ is idling at 850.  :D

David

Hello, I just bought an 82 Vision and my tach does not work.  I don't understand about you putting the two plugs together and tapping into the gray wire.  What do you mean by tapping into the gray wire?  Do I need extra wire?  Or did you wire the orange and gray wire together?

[fret not]

You need either the orange OR the gray wire for a tach signal.  It seems YJ's bike has some parts from two different years, so he connects a gray to an orange.  Most of our bikes will not be doing this.  The main point is to get ONE coil signal for the tach.

[undertaker]

OK.  Figured it out today and finally finished the job.  I now have a fully functional tach.

On the gauge side of the wiring harness, its the orange wire.  On the wiring harness, its the gray wire.  When I put the two plugs together, the gray and orange wires line up.  I tapped into the gray wire and fired her up and Voila!  I have a nice steady tach.  WOW... YJ is idling at 850.  :D

David

This is how my plug is.  How do I "tap" into the gray wire ?????