I've wired everything correctly for aftermarket KOSO tachometer. However, the tachometer does not work. The yellow/green on the wiring diagram is the tachometer signal for the OEM F2. However, when I've connected it to black/yellow (RPM) on the aftermarket tach, it doesn't work at all. The tach is dead and doesn't move at all. However, when I plug in my OEM gauge cluster, it works fine. Is it because the aftermarket tach is digital? I don't understand. Am I supposed to directly splice a connection into one of the coils? My KOSO gauge powers up correctly and everything including the turn signals, neutral light etc all work except my tach! I'm so confused.

 

which koso tach are you working with? Some of them aren't intended for non Fuel injected bikes.

Also - I just pulled up several installation schematics for random of their moto tachs, and on all of those, the tach wire in the koso cluster was brown.

 

I believe it is the Koso RX-2N GP style. However, the one I have is a clone of it. From what the seller on eBay told me was that there are supposed to be two connections/wires from my bike to the receiving end of the gauge. So 2 wires from my bike to the tachometer/RPM signal wire. Does that sound right? All I see from my OEM wiring diagram which makes sense is the green/yellow wire.

Here is the wiring:



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I've connected the the black/yellow (RPM) to the yellow/green on the F2 and the tach doesn't work.

 

I have the RX-2ns hooked up to my F4 and its the brown wire that receives the rpm signal, for the wiring diagram that you posted up are those wires bike side or tach side. Ill look for a wiring diagram for the F2 but here is the one I made for the F4 I hope it helps a bit.

 

Here you are hope this helps and the F4 and F2 are very similar as far as the tach wiring goes so you can use the above wiring diagram in conjunction with this to make it work



Also, the brown RPM wire is the one that has a bullet connector attached to it, you need to remove the bullet connector to solder the wires together.

*Disclaimer* This is based off of an actual Koso RX-2n gauge, if its a clone I cant guarantee that its wired the same.

 

there aren't 2 signal wires in the F2's harness, so no what the seller told you doesn't seem right.

CJardine's diagrams/info is correct for a real KOSO - Bike's Yellow/Green is the signal wire to a KOSO Tach's brown - obviously from what you posted though you have a different color code.

some aftermarket tachs don't even connect to a wire, they wrap around a sparkplug wire or coil signal wire and picks up the signal inductively. Again, not saying that's what you need - it is just for general info.

I just pulled up a couple of ebay auctions for these china-sourced digital speedos, and reading the instructuions from several vendors, I'm inclined to think you need to wire it to a different signal source.

from an ebay posting: 11x1000 RPM LCD Digital Odometer Speedometer Tachometer Motorcycle w Backlight | eBay







11X 1000R/Min is also Available

Please contact if required





Red line: 12V power supply (positive)
Black line: power lock switch
Green Line: the negative power
Blue Line: beam indicator
Orange line: left turn signal
Light Blue: Right turn signal
Yellow white lines: oil table line
Blue white line: Water temperature gauge
Green, yellow line: brake lights line
Black yellow lines: tachometer line





Multi-function:

tachometer
odometer
fuel level
clock

Fit for:



4 stroke motorcycle
disc-brake front tire

17 Inch tires (default as 17", if your tire is 10", 12", 13", 18", 19", 20", or 21", please contact us before bidding).
Your panel might need to be modified by yourself to fit the meter.


Specifications:

Operating temperature: -30 ℃ ~ 80 ℃
Storage temperature: -35 ℃ ~ 85 ℃
The Power voltage: 12V DC
Backlight: blue


Installation Notes:

Engine rotate speed comes from the ignition signal. The sensor wire is normally contacted with the positive side of the magnetor or directly wired on the rectifier.

 

Thanks for the info. I've been caught up on lots of things this week and haven't had the time to look carefully. So if my yellow/green wire isn't the one, then I will have to wrap it around the spark plug? I've tried both ends of the coil, both negative and positive but still no signal.

 

Man - without the parts/pieces in my hands, I just guessing, and don't think I'm going to have an answer for you. Best bet would be to find someone that is using that same model tach and see what they did.

 

Ok, so I found out what was wrong. The Tachometer is broken! Totaly facepalm moment. If only I had used the right tools to diagnose the problem... As I suspected, the tachometer itself is faulty. I confirmed it today. Thanks for all your help! I'm going to RMA/return it and hopefully get another one that isn't broken.



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Let us know when you get it sorted, would like to see what your end result is