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Wiring Chinese Koso Replica RX2n gauges

90K views 48 replies 18 participants last post by  Mattson  
#1 ·
I have these replica Koso RX2n clocks on my bike. This is a generic picture, but it shows which ones I mean. For ref, my bike is a 1993 Honda CBR600F2.


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I can find a lot of posts about the RX1, but it is a different gauge, so the advice given doesn't seem relevant. This one is actually called an SS182 but seems identical to the Koso RX2n.

So far I have it wired up so that it does the startup sequence and lights up. The indicator lights, headlamp main beam, neutral light, engine, battery lights etc.... all work fine (except for the fuel one which blinks on and off all the time as I don't have a fuel gauge on my bike so I just covered that one with black tape as it was a bit distracting).

My problem is the RPM which I can't get to work at all (except when the needle moves on start-up sequence). Do I attach something to the coils to get this reading? And is it the + or the - end of the coil? This is just a guess based on what I can find elsewhere about the RX1 gauges, so I may be way off. I have also heard of people wrapping wires around the HT leads, but this seems to be a less accurate way of doing it.

The other problem is the speedo - The magnets are fixed onto the front brake disc and the sensor is set up about 5mm from them. I get a reading, but it is way out and sometimes jumps from one speed to another erratically. I think this is due to the setting for the wheel size - My bike has 17" front wheels but the setting only goes from 1000-2999mm. Does anyone know what figure I should be putting in here?

If anyone has any info on these clocks or has fitted them successfully, could you please point me in the right direction. If the info I need is already out there, can you let me know where as I can't find it. Thanks

The only info I got with the clocks is posted below and not much help:

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#6 · (Edited)
Thanks for your responses :)

I have already tried wiring it to the old RPM wire and nothing happens.

The speed sensor can go a bit closer, but I thought it was meant to be about 5mm away from the magnets?

I will try to measure the wheel as you suggested, I was just curious if anybody else already had that measurement for a 17" tyre as there are a lot of aftermarket clocks out there which require that figure.

Forgot to mention that the odo and the trip work fine - it remembers both after being switched off and on again - but strangely, I can't get the clock to remember the time. That one is a head scratcher as there is obviously some form of power or memory there.
 
#8 ·
I have a17" wheel and the tire I have is a 60/120 I believe with a toll out of 1810mm. That may get you closer. Strange the factory tach signal wire didn't work.

Sent from Motorcycle.com App

Thanks - I will try that number and see what happens :)

Yeah, the whole thing is strange - even tried the wires back on the old clocks to make sure they still worked on that, and they did. The only comfort I have is that I know that a lot of people have problems wiring these types of clocks, so the answer may be out there somewhere - I just have to find it LOL
 
#10 ·
Thanks for popping in Taz - Any help would be greatly recieved. Overall, I love the clocks and the way they look, just wish I could get them to work properly cos the RPM part is the best looking bit and mine doesn't want to play :confused:

Just wondering why this is the third set of gauges you will have used? What happened to the other two?
 
#11 ·
The first one was a Koso DB-01R. Problem there was it was a bit too small and to get some of the idiot lights working would have meant messing around with relays.

2nd set was one of the cheaper Chinese gauges but I think I blew that one up by not fitting an inline fuse for the battery connection. The idiot lights on these gauges worked fine but the magnet setup for the speedo was a bit sketchy as it looked like you needed to drill holes in the brake disc to fit them.

I am hoping that with these gauges the magnets fit into the heads of the disc bolts. If this is the case I will bin the supplied magnets and get some bolts which are hexagonal head instead of the button allen head bolts which already have the magnet fitted in them. I would always worry about magnets falling off and that would solve that problem.

On the Koso gauge you had to enter the wheel size which even when I measured it with string the speedo was still out. In the end I used a GPS speedo app on my phone and fine tuned the wheel size setting until it matched the speedo app.
 
#12 ·
I found the magnets didn't fit in the bolt heads either so I JB welded them just to be sure and that meant the sensor bracket had to be moved back a little as they weren't flush.
 
#14 ·
I have this gauge and spoke a lot with the manufacturer in China. I was thinking about importing some to sell to you guys. However, they are obviously direct knock-offs from a product that KOSO sells in the USA, so I thought it wouldn't be a good business option!

Unfortunately, this gauge is set up to read the RPM signal from the NEGATIVE 12v signal which comes from the SIGNAL GENERATOR. You can not use a positive 12v signal from the ignition coil. This is the part that sucks ... the gauge is calibrated for a single cylinder engine. That means, in most circumstances, a 4 banger will read 4x higher and a two cylinder will read 2x higher than actual RPM. The signal is presented in Mhz, so you really have no way to modify the output from the signal generator (because it runs the ignition) and no way to change the signal without adding your own circuitry.

As for the wheel, you can measure the length from the front axle to the ground and use that as your radius to calculate the circumference. Don't forget that this gauge has a variable PULSE setting to set for the speedo. If you have two magnets, make sure you set the PULSE to 2.
 
#20 ·
I have this gauge and spoke a lot with the manufacturer in China. I was thinking about importing some to sell to you guys. However, they are obviously direct knock-offs from a product that KOSO sells in the USA, so I thought it wouldn't be a good business option!
I disagree that it wouldn't be a good idea - The clocks are selling rather well from the amount of posts I see about them on the internet. KOSO ones are just too pricey for a lot of people so there is a thriving market for the Chinese knock-off ones. If you were to sell them instead, it would reduce the waiting time for them to arrive in the post, and would be easier to ask for advice on fitting them. I say, go for it - and when you make millions, can I have a 10% cut for persuading you to do it? :LolLolLolLol:
 
#17 ·
The 'cylinder number' think is a bit misleading really - it's more about the number of independent coil packs (like my ZZR has four coil packs now as I've converted to sticks, but there are only two 'independent' sides; 1&4 is one signal, 2&3 is another).

My Koso came with two spade crimps joined together with a short length of wire, and a longer length of wire tapped off. This was to fit between the connector and the coil itself.
Difficult to see here but it's the blue/yellow wire n the left
 
#19 ·
Wow - I go away for a couple of days and all of a sudden there are lots of replies to my post :)

Thanks to all of you for helping me out with this. My wiring guy has sort of given up on my clocks which has frustrated me as I didn't buy them so they could sit there and not work!
I have read somewhere else that its not the number of cylinders, but the number of coils that you have to put in the clock. When I find that again, I will post it on here for others to see.

I will try to get him interested in finishing my clocks, so then I can report back.
 
#22 ·
I have just discovered the old adapter I used to drive my DB-01R clocks off the mechanical speedo on my Ace.

http://www.digital-speedos.co.uk/mechanical-to-digital-drive-converter-type-m-for-whiteblack-thin-square-plug-models-159-p.asp

These are the installation instructions

http://www.digital-speedos.co.uk/cable-drive-adapter-292-p.asp

I presume this uses a mechanism to turn the revolutions of the mechanical speedo into the sort of electronic pulses that the magnets passing by the sensor would use. Does anyone know if this would be usable on these Chinese gauges?
 
#23 ·
I presume this uses a mechanism to turn the revolutions of the mechanical speedo into the sort of electronic pulses that the magnets passing by the sensor would use. Does anyone know if this would be usable on these Chinese gauges?
It's a very similar mechanism, however, the three wires make me skeptical that it would work with the knockoff Koso in this conversation. Most magnetic hall-effect pickups from the chinese manufacturers utilize a 5v signal to the hall-effect sensor. That's what the third wire is. The signal generator on most motorcycles utilizes a 12v signal. Sooo .. you might be able to McGyver something if you wire it in parallel with the signal generator .. but if the magnet count in the sensor is wrong, you will still have the same problem.
 
#24 ·
I will pass all the info on to my mate and see if it makes him go - "Ahh! Now I get it" LOL

All the info I have is based on the KOSO, so the info you have provided will be far more relevant - Thanks both of you :)
 
#26 ·
Got my gauges today and had a few problems:

1. No magnets. I am going to use magnetic bolts but I have messaged the seller to send me some as I will keep them as a backup.

2. Wires don't match the information sheet entirely. Some that are meant to be a solid colour are striped and I have a purple wire that doesn't correspond to anything. Does anyone know what this might be for? I have messaged the seller who might be able to provide an answer.
 
#27 ·
MORE PROBLEMS....

One of the wires was the wrong colour. It appears that what should have been the brown wire pin 19) which is the battery connection was actually purple on my clocks. This is supposed the maintain power to the gauges to keep time correct, but when I turn off the ignition, the clocks are dead and when I turn the ignition back on, the time is reset.

I spent ages looking for the red wire which +5v even though I am not sure what this is for. I then realised that maybe it should have been spliced with the red wire for the speedo sensor like the blue wire. Lo and behold, no splice on the red speedo wire, so I spliced it myself, though I am not sure what the red wire is supposed to connect to as there is already a wire for a switched positive (black), which I have connected to the live that powered the motor on the rev counter.

Thirdly, the ring of LED's that is supposed to light up in sync with rev counter needle is not working!!!

I have contacted the seller to see if I am doing anything wrong, though I don't beleive I am.
 
#28 ·
Sorted out a couple of problems which were down to me being a numpty. I sorted out how to change the cylinder number after I read the instructions properly.

The red wire I spliced didn't need splicing as that is just the positive feed to the hall sensor.

However, the direct battery connection is still a problem. I have tried connecting this directly to a spare battery and the gauge comes on for a second and then goes off again. As I understand it the clock is meant to be permanently on.

I have contacted the seller who said to return it if faulty, but I don't want to have to wait for the gauge to get back to the seller and then another one sent out as they are coming from China, so I will just do without the clock and the LED's that should light up with the rev counter. Now I need to order the magnetic disc bolts to get the speedo working!!
 
#29 ·
I am beginning to think that these gauges are more trouble than they are worth :(

They may be cheap(er) than the KOSO's but as you say Taz, you don't want to have to send them back and wait for another set from China. Yours don't seem to be working properly and neither are mine.

My mate has explained that he is very reluctant to try to connect any more wires without a proper wiring diagram for the clocks - He doesn't want to damage the clocks or the wiring on my bike if he makes a mistake, so thats fair enough. So I am stuck with no rev counter and an inaccuarate speedo and odo. Past caring at the moment - I will just have to carry on looking for the answers/wiring diagram but the bike runs without the clocks working properly, so that will have to do for now.
 
#30 ·
My rev counter seems to be working OK off the stock wire for the OEM gauges, but with one quirk.

On the Ace it has a diagnostic tool which works through the rev counter. It will move the rev counter needle and keep it there for a few seconds to indicate the fault. 8K indicates a problem with the fuel system. In my case it threw up the code because I no longer had the original fuel warning bulb wired in!!!

Now on the default setting of 1 cylinder it ran to 8K. Now I amended the cylinders to 2 (4 cylinders, but 2 coils) and it indicated 4K which is not an error code!!!!.

I am having problems getting the bike started at the mo so I don't know if it will behave differently when actually running, though I don't see why it should. I am going to order some magnetic disc bolts and see how I go with the speedo.

I will set it up as per instructions and then use the GPS on my phone to fine tune it until it is correct by increaring/decreasing wheel size.
 
#31 ·
I read all the thread because I am very interested in one of this speedometers.
I see them nice and cheap.
If I do not understand bad, the rpm wire should be connected to the pulse generator, called pickup coil, I am right?
This is the pickup coil for my bike, the little sensor with two wires, green and blue, they have current AC with 1,5 volts to 6 volts accelerating.
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Where should the rpm wire be connected? to the blue, to the Green or it does not matter.
Thanks