Koso Tachometer/speedometer on GS 1000

[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-inf...ug-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.

[John Kat]

I had another go at getting the tachometer to work today.
First, I tried to wrap about 8 coils of wire around one of the spark plug leads and despite changing the polarity of the input, I got no rev indication whatsoever...
Next, I went back to connecting the tacho input wire directly to one of the coils but this time I used a 24.7 K ohm resistor in series.
The result is still very disappointing: at idle it works fine except for the needle that dips from time to time but when the engine revs above 4K rpm the needle wanders up and down by approximately a 1000 rpm.
Great! I didn't need a rev counter to get this level of approximation...
Koso North America answered my request for help by saying that I had to call Koso Europe.
That's very kind except that I bought the device from the USA as it is NOT sold in Europe.
No fun so far!
Update: I got an answer from Koso in Germany!
They stated that I had to get the signal from the electronic ignition pick up sensor.
It was in the manual but for some reason I didn't register that possibility...
I'll try tomorrow!

[John Kat]

Following Koso Europe's advice, I wired the tacho input wire to the electronic ignition pick up sensor.
I chose the blue wire and bingo IT WORKS
The indication is very stable from 1000 to 8000 rpm.
The good news is that I realize that I'm must have been shifting 1000 rpm too early before...
Gone is the hesitation of the original 30 year old instrument cluster.
I would highly recommend the device at least if you have an electronic ignition on your bike.

[Chris G]

Good stuff, I looked at mine earlier it was installed before I bougt it, but there is no wiring wound around any of the coils, plugs etc, appears to be as you state and wired direct to the coil pick up.

[Wheelbreak]

Following Koso Europe's advice, I wired the tacho input wire to the electronic ignition pick up sensor.
I chose the blue wire and bingo IT WORKS
The indication is very stable from 1000 to 8000 rpm.
The good news is that I realize that I'm must have been shifting 1000 rpm too early before...
Gone is the hesitation of the original 30 year old instrument cluster.
I would highly recommend the device at least if you have an electronic ignition on your bike.

Thank God for this thread!! I was ready to chuck this thing off a cliff. I just spliced to the blue wire you indicated and it's working great now!! The connect to the pick up sensor graphic in the instructions was confusing to me, and I tried every other method that pertained to my bike with no luck.

[John Kat]

Thank God for this thread!! I was ready to chuck this thing off a cliff. I just spliced to the blue wire you indicated and it's working great now!! The connect to the pick up sensor graphic in the instructions was confusing to me, and I tried every other method that pertained to my bike with no luck.

Glad it worked for you!
For some reason, I also got confused by the instruction sheet?

[Wheelbreak]

Quick question. Do you have any issues with your battery draining? I have read other people have this issue as well, and am wondering if it is my wiring job.

I ran a new wire to the battery +terminal for the red constant power on the koso. Used the orange wire that powers my lights to the brown wire on the koso for the ignition on power. Then I use one of my spare black and white grounds in the headlight bucket for the ground.

The gauge works well, but my battery seems to be draining. I am going to order a new battery today to start from scratch because my old battery will no longer hold a charge. This is ridiculous because it's only a year old.

[John Kat]

Quick question. Do you have any issues with your battery draining? I have read other people have this issue as well, and am wondering if it is my wiring job.

I ran a new wire to the battery +terminal for the red constant power on the koso. Used the orange wire that powers my lights to the brown wire on the koso for the ignition on power. Then I use one of my spare black and white grounds in the headlight bucket for the ground.

The gauge works well, but my battery seems to be draining. I am going to order a new battery today to start from scratch because my old battery will no longer hold a charge. This is ridiculous because it's only a year old.

I haven't paid particular attention to this so far but I could measure the current consumption for you.