Koso speedometer wiring

Hey guys, 

So I've got a model EX-02 Koso, heres the wiring instructions

I'm struggling to get my head around that the original dash had 2 wires for every light, Am i right in thinking i only need to take the positive feed for all the lights and the negative for the neutral?

also the coolant temperature guage wires, the koso has one wire marked +/-

Right. Doesn't look too bad.

Firstly to explain:

The oil pressure, neutral and sidestand lights all have a permanent positive (+12 V) connection and are 'negative switched' i.e. the negative (earth) connection is switched to control the light.

The turn signal(s) and the high beam all have a permanent negative (0 V, earth) connection and are 'positive switched' i.e. the positive (+12 V) connection is switched to control the light.

So some of the switched connections are 'positive' and some are 'negative'.  The KOSO box has both permanent positive and negative connections, so can deal with either type of input, as long as it is connected to the right place.  The little + and - signs on the KOSO diagram indicated which inputs are  positive and negatively switched.

Thankfully all the inputs to the KOSO match up with how the CB500 wiring works.

Because the KOSO has separate positive and negative connections you will only need to wire up one wire from/for each light - the important point is selecting the correct one!

So this leads us to the connection table:

Function	Honda Wire colour	KOSO wire colour
Right indicator	Solid light blue	Blue
Left indicator	Solid Orange	Orange
Oil pressure	Blue with red stripe	NOT CONNECTED
Neutral	Green with red stripe	White
High beam	Solid Blue	Yellow
Sidestand	Yellow with black stripe	NOT CONNECTED
Temp. gauge	Green with blue stripe	Yellow/white
Positive power /12 V	Black with brown stripe	Red
Negative power/earth	Green	Black
Engine light/ MIL	NOT CONNECTED	Purple

Note I have also provided some connections for the power - there is a possibility you will have to put a extra ground wire in which goes back to the battery and/or an extra power connection straight from the fusebox, but it seems stupid not to use the power that is already there (it might well work and is fused already).

Before doing this use a multimeter to check that the black/brown wire on your bike is connected to +12 V and the green wire is connected to 0 V/ earth/negative. I don't know why it wouldn't be the case, but it would be a good sanity check.

Also, it might well be sensible to remove the battery before hacking around with the wiring (reduces the chance of problems!).


Do check my working!  If there is anything that doesn't make sense then do ask - I might have made a cock up!

Best of luck...

Great write up mate, installed and works perfectly, I couldnt get power using that earth  so ive just found a ground on the forks and also I connected the oil pressure wire to the koso engine warning light because... because. 

Thank you muchly! 

siNN wrote:Great write up mate, installed and works perfectly, I couldnt get power using that earth :scratch: so ive just found a ground on the forks and also I connected the oil pressure wire to the koso engine warning light because... because. 

Thank you muchly!  :cheers:

Cool, glad to hear it works. I did think about suggesting that (oil pressure light -> engine warning light) but I didn't know if it would work, so I thought it best to try and keep it simple. After all, if the oil pressure light comes on then your engine is certainly trying to tell you something...