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KOSO RX1N Tacho
twybrow - 30/10/07 at 10:10 AM

I have been installing my Koso gauges for a while now, and finally got around to looking at the tach. The engine is a Triumph Daytona (with integral coils - no spark lead). I have tried two arrangements so far:


Koso tacho wiring
Koso tacho wiring

This diagram is as it is currently connected. I have also tried off the +ve side (marked with an x) as the instructions say (if you can understand the English!).

At present, coming off the ECU side of coil 3, I get really irratic tach reading, jumping all over the range.

- Can anyone suggest why this may be occuring?
- How crucial is it to come off of coil No. 1 (as again, the instructions do sort of say you should come off coil no. 1)
- Any other comments/suggestions?

Thanks.

twybrow - 30/10/07 at 12:58 PM

Come on, someone must understand these things...!?

chockymonster - 30/10/07 at 01:50 PM

I just soldered mine into the feed to the bike clocks.

twybrow - 30/10/07 at 03:43 PM

I got nothing from that (although I may try again)... My bike clocks are fed from the ECU, not the coils.

02GF74 - 30/10/07 at 03:53 PM

quote:
Originally posted by twybrow
Come on, someone must understand these things...!?


Many of us, like myself do understand the concept and how these things work but w ithout knowing the specifiaction for the coil pack and rev counter, guess work is involved whcih may result in non funcitoning or at worst, damaged components. Nobody wants to supply bad info., well not on prupose.

Can you not get any info, from the seller of the rev counter?

Are the coils siwtched to earth by the ecu - like a standard coil?

The switching of the coil causes nasty spikes - funnily enough I experienced this the other day when rewiring my dash & speedo - so the signal may need conditioniong if the rev counter origoinally had an inpout from an ecu. Something like a zener diode/resitor to limit the signal, maybe a capcitor to "smooth" it - but this is guesswork.

So in short, the coil is most likely to be switched to earth but we don't know the signal the rev counter needs.

Also rev counters connect to one coil that feeds all four cylinders so won't your counter show 1/3 the true rpm? Or is it programmable?

twybrow - 30/10/07 at 04:19 PM

I understand the concept of how they work, just not the exact detail of why it wont work!

I would never hold somone liable for info given on here. We are amateurs, posting tips/advice. If I were paying you for the advice, I would hold you accountable!

The coils are switched earth via the ECU as you suggest. The clocks (KOSO) are fully programmable - you can vary cycle type (2/4 stroke) and cylinder numbers (1, 2, 3, 4, 5, 6, 8, 12). As previously mentioned, the coils are mounted directly on top of each spark plug (ie one coil per plug, not one coil 4 plus).

The instructions (with their very dodgy english translation) suggest there are 3 ways to input the rev signal.

1. - wrap the wire around a spark plug wire (inductive signal casued by the current in the wire)
2. - connect to the POSITIVE electrode terminal (I cant see they mean the +ve side, as that is not switched or varying at all)
3. connect to the 'digital speed pick up' - not even sure what they mean here - I think the crank position sensor

I know what you mean about the use of diodes/capaticotrs. I thought about this too - I just find it strange that the manufacturere assumes everything should work just fine without them.

Are there other Koso users out there who have gone thorugh similar issues?

dave r - 30/10/07 at 05:06 PM

i am having similar issues with mine, have sort of given up on it for a while... will be following this with interest

twybrow - 31/10/07 at 08:18 AM

After much fiddling and rewiring, I am now able to get a stable reading directly from the ECU. PReviously, I had tried this with no luck - today, it seems to be working! I will still need to play with the settings, as I suspect it is reading 3 times higher than it should do at present (either that or my idle speed is 4000rpm!). Thanks for your help chaps.