I just purchased this tacho,
brand is Kyoritsu K-80B

i got little idea how to wire it.

it only has a few markings is a '+' on the bottom . The 2 bottom ones are also wired together. Then there is an L at the top with 12v. Also says the number 8042 on it, if that meants anything

Excuse the pic (taken with my phone)

the marvels of paint.

My guess is that bottom is 12V top is GND and the centre is signal from coil? which side to use...who knows

i'm pretty sure mine has 4 wires:
earth
+ign
input wire from coil
and + for the illumination

the 2 wired together are proabbly the 12v ign and ill+
so it powers up and illuminates when u turn your ignition on

hope this helps
Joel

had a look at it with the multimeter tonight. Top 2 are connected together. My guess is that it is 'signal' and case is gnd.

only one way to find out....

cheers dub74l, got me on a role..

yep, one way to find out (same way that i did mine) easiest to play with 2 pos and a ground first (using a circuit check light as the ground) as you will see the needle leap across when you hook the power to the ignition imput (at least i think that's what i remember. if you are running a new wire to the ignition all the way down the car MAKE SURE IT IS WELL INSULATED! mine got too close to my exhaut, melted, and shorted the coil out when i tried to start

Hi all i revisited this today (its been sitting there for a while)

I have made progress but it is still not working properly.

The top two are for illumination (horray i can see light)

the bottom two must be for signal and gnd.

When i connect gnd and the -ive of the coil i get a reading that bouces around heaps at about 4-6k.

Is there something i am doing wrong? Is there something i am meant to put inline with it?

Cheers for any help

James

Gnd is most likely for ground, connect this to earth ie connect it to the car body. the other one will be signal wire from the coil (-ve or terminal 1 on the coil). The two screws on the side probably just hold the tacho together and are not electrical connections.

cheers T3

I have it working but its registering a huge value at idle. It bounces around (real fast) between 4 &6k.

I put the cheap tacho that came with my timing light on and it worked fine. Is there something that i possibly might need to put inline to make it work? Its an old tacho, possibly they used to wire them differently. Possibly needs to be divided by 4?

Cheers
James

Hate to ask the obvious, but are you sure it's for a four cylinder? What is the difference in reading between your cheap timing tacho and the kyoritsu? Could be that your new one is for a 6 or 8 cylinder.

Sounds like it may be for an eight cylinder car.
Seeing it has 80B on the box.
Its strange the cylinders aren't written on it.

Many [user friendly]Tachometers have a cylinder switch on the back.
Just select what engine You have, unless You have a 5 cylinder VW transporter...
then You have problems.

I have two identical VDO tachos and one is very simple to hook up
the later one looks very complicated with many different connections.

I don't know of any way in which You can change the Tacho to 4 cylinders
You could pull it apart and see if there is a switch inside
My guess is there isn't

Lee

i was worried it might be for a dif number of cylinders.

I would of thought though that 8 cly would mean more pulses hence a higher reading.

so running a 8cyl tacho on a 4cyl car would end up in a really small reading??

the other option is someone on this forums sold me a dud... It allready is half an inch bigger than what it was meant to be

None of the insulated terminals is going to be ground. This just wouldn't make sense. It may need both +ve and -ve coil terminals connected, maybe for resistance/Pd? So the two currently wired together are like DUB74L said probably main power and illumination, the other two for coil.

Maybe

well i know the top 2 are illumination, why may u ask? cause when i connect one to gnd and the other to +12 i get a pretty green light :bounce

I will try the positive and negative of the coil with the case to gnd, see if we get a difference

Cheers for the help guys:thumb

btw my cheap tacho reads about 900 at idle.

new tacho is unreadable...it bouces between 4k and max...very quickly.