Koso Tachometer/speedometer on GS 1000

[John Kat]

After spending countless hours on refurbishing old GS 1000 speedometers and tachometers, I decide that my resto-mod GS 1000 XP (with full GSXR 11K suspension) would be upgraded to a Koso T&T multifunction gauge.
It's a very smart piece of machinery as there is a stepper motor for the tachometer and a digital display for the speed.
What's great is that it comes with a sensor and some magnets that will fit to the front disk in order to compute your speed.
Today, I wired up the electrical part.
To do so I used the existing cord of my defunct GS 1000 cluster and soldered the wires to the Koso cluster.
The color codes go like this ( Koso first, GS 1000 next, function):

Red, Red, +12V unswitched
Dark Brown, Yellow Black, Tachometer ( see below)
Yellow, Yellow, High beam
Orange, Black, Indicator
Blue, Pale Green, Indicator
Light Brown,Orange, Switched 12V
Grey, Yellow Green, Oil pressure
Black, Black White, Ground
Purple, Blue, Neutral

For the Tacho function, I "borrowed " the yellow black wire that's normally used for the fuel level.
I reconnected this wire to the switched side of one of the coils.
For the +12V unswitched (red) I hooked up a separate wire directly to the ignition switch.
Don't try to connect it to the switched side ( orange) of the +12V it won't work.
Last but not least don't forget to bolt the support bracket in place before soldering the wires as the GS 1000 plug will not fit through the whole in the bracket...
A couple of pictures:

 

[2BRacing]

I like the look of that! What are you going to mount on the left hand side?

 

[BigD_83]

At first blush, there's a little too much modern in that "mod" for my tastes, but I can see the appeal in putting all the function in one dial. Clean up the lines, etc...

Trying to wrap my head around that big hole just left of the gauge. What was originally there? I think it would look even better with the new dial centered in that hole.

 

[Chris G]

Looks good, I have a Koso unit fitted to my project bike (not by me) all functions are working though it was reading way over on MPH, I found the tyre circumference setting was a little out, but the main problem was the amount of magnets fitted into the rotor fixing studs, after a bit of research my wheel has 5 fixing studs so you either fit 1 magnet (reading not as consistent / lag) or you fit 5 to give a more constant stable reading, but the clocks have to be told how there set, found mine was set to 1 but has 5 magnets fitted, this caused it to read so inaccurately.

 

[Chris G]

Trying to wrap my head around that big hole just left of the gauge. What was originally there? I think it would look even better with the new dial centered in that hole.

for me I'd find a nice analogue watch to fill the gap

 

[BigD_83]

for me I'd find a nice analogue watch to fill the gap

That'd work, too.

 

[John Kat]

I like the look of that! What are you going to mount on the left hand side?

I mounted the Koso T&T gauge on the RH side first and foremost because it was the easiest way to do so.
Of course the gap on the LH side is an invitation to fill it.
I'm tempted to do so with a round AFR meter as I'm always wondering wether my bike is tuned correctly?
AEM has such a model but I don't know if it's rugged enough to be used on a bike?
Or this one: http://www.innovatemotorsports.com/products/MTXL.php

 

[John Kat]

Today, I installed the inductive pick-up probe for the speedometer.
It gets it's signal from small magnets that are inserted in the cavities of the bolts that hold the front disk.
Very smart!
This was possible on my bike as I'm using GSXR 1100 disks.
For a std GS 1000 one must purchase an active transducer that can work off the std disk bolts.
The good new is that you can program any wheel you like to get the correct indicated speed.
A bonus to me as I'm using 18" wheels on the larger spindle that comes with the GSXR 11K fork that forbids the use of the mechanical pick-up designed for it.
Here's what it looks like:

 

[Chris G]

How tight are these magnets ? Is it possible to remove them if the disks need changing in the future, mine was fitted prior to buying the bike don't have any instructions I had to find every through the net regarding some of the settings.

 

[John Kat]

The magnets are very strong but it should be relatively easy to pry them out of their recess with a small screwdriver.
If you need the instructions, I could post them here?

 

[John Kat]

The magnets are very strong but it should be relatively easy to pry them out of their recess with a small screwdriver.
If you need the instructions, I could post them here?

I discovered...that the magnets need to inserted the right way around.
Failing to do so the speed indication will not be correct.
To get the magnets out there is only one way: use a spare magnet!
Luckily, I had used only 5 of the 6 magnets that are provided in the kit and by placing the spare magnet on top of those in place it was very easy to disloge them.
The spare magnet also allowed me to check the orientation of the magnetic field as it will eitheir stick to the middle of the magnet or be repulsed to one side of it.
I believe all magnets must be oriented with the North pole towards the outside of the wheel.

 

[Chris G]

Yes all must have there N pole facing out, I though about using another magnet as the removal tool, glad it worked. Don't forget you have to change the setting to how many magnets are fitted, i.e. 5 if you don't you'll end up with it reading way too high, this was the problem I had, plus tyre circumference was set wrong.

 

[John Kat]

I went for my first ride today!
The engine idles smoothly at 1100 rpm and the speedometer works perfectly as all other functions.
The only issue is that when the revs go above 4K rpm the needle goes up and down in an erratic manner?
The manual says that when the Tacho is connected directly to the coils, one has to use R type plugs?
I suppose this means some kind of resistor in series with the plugs?
Any idea?

 

[BigD_83]

The R (resistor-type) plugs suppress ignition noise (EMF) that might interfere with the gauge and other electronics:

http://www.ngksparkplugs.ca/tech-info-spark-plug-faq.cfm#sp9

 

[hillsy]

I mounted an Acewell on one of my bikes and it came with a 1/2 watt resistor to put in line with the tacho pick-up wire if the readings were erratic.

I can't recall what size it was though.

Also, you can mount the speedo pick-up / magnets on the rear wheel to keep the front end looking tidy.

 

[John Kat]

The R (resistor-type) plugs suppress ignition noise (EMF) that might interfere with the gauge and other electronics:

http://www.ngksparkplugs.ca/tech-info-spark-plug-faq.cfm#sp9

Good info!
At least I have the BR 8ES plugs where the R stands for Resistor.

 

[John Kat]

I mounted an Acewell on one of my bikes and it came with a 1/2 watt resistor to put in line with the tacho pick-up wire if the readings were erratic.

I can't recall what size it was though.
.

I followed your advice and mounted a 4.7 Kohm resistor in series with the Koso Tacho input.
The Tacho works better but still doesn't register the engine revs above approximately 4000 rpm...

 

[Chris G]

I know your clocks are different to mine, but there are a few crucial things that need doing in the set up I assume yours will need the same info. Cycle and Pistons needs to be told if it's a two stroke or four stroke and the corresponding number of Pistons need to be input, also there is a input signal that can be changed between Hi and Lo change between them for best results. The online instruction manual for mine also shows diffrent methods of connection to the coils, pending on the electrical system of the bike some require wrapping the rpm wire a min of 5 times round spark plug cap, or taping it to the coil lead, I can send a link to you of this manual if it helps.

 

[John Kat]

I know your clocks are different to mine, but there are a few crucial things that need doing in the set up I assume yours will need the same info. Cycle and Pistons needs to be told if it's a two stroke or four stroke and the corresponding number of Pistons need to be input, also there is a input signal that can be changed between Hi and Lo change between them for best results. The online instruction manual for mine also shows diffrent methods of connection to the coils, pending on the electrical system of the bike some require wrapping the rpm wire a min of 5 times round spark plug cap, or taping it to the coil lead, I can send a link to you of this manual if it helps.

Thanks Chris but I've gone through all of that and the proof is that the engine idles nicely at 1100 rpm as indicated on the tacho.
The problems start as I build up the revs.
Up to about 4K rpm it's almost OK but thereafter it becomes erratic.
I've written to Koso and I'm waiting for their reply.

 

[Chris G]

Good stuff, hope you get it sorted.