Koso gauge RPM set up

[DomP]

I've fitted a Koso multifunction gauge to my cb550 with the rpm wire connected to the positive of one of the coils.  I can't get it to register anything on the rev counter regardless of the settings I've entered.  Has anyone else on here any knowledge of Koso gauges or similar set ups?  Im trying not to bother Roo again😀

[paul G]

Have you wired the rest of the functions up sure mine had a common wire for something but it was ages ago.
What model is it.

This was the one I used.


https://www.digital-speedos.co.uk/gauges-c4/motorcycle-gauges-c27/multifunction-gauges-c29/multifunction-gauge-db-01rn-p5

[DomP]

All wired up and everything works except the tacho, it's a TNT D64 Paul.

[Bryanj]

Aftermarket tachos on cars used to connect to points side of coil

[DomP]

Aftermarket tachos on cars used to connect to points side of coil

I'll check later but I 'think' I got it right

[DomP]

I'm running a Dyna S that came with it when I bought it, whether that affects things

[McCabe-Thiele (Ted)]

If it works on the  LT side of  the impulses will it not be related to the number of sparks generated for one crank rotation?
Not as such affected by the HT coil side?

[DomP]

I'm not sure I understand Ted.  The instructions are woeful, in the setup guide you have to select for 4 stroke and 4 cylinders by selecting options that go 0.5, 1, 2, 3, 4 but on my gauge there are .5 increments that don't relate to anything in the instructions.  It's to chose the number of ignition per cycle.  Clear as mud to me.

[Bryanj]

A "standard"  electronic tacho will count 4 lt pulses for 1 crank revolotion, the honda coil will pulse twice for one crank revolution so readings may well be wrong, also with the dyna there is a different amount of "dwell" or coil charging time which may afect the tacho operation, i cant comment on that as i understand electrical dohickies but not elctronical ones

[McCabe-Thiele (Ted)]

An electronic rev counter works by converting the rotational impulses into either a digital or analogue display.
A rev counter for a 4 cylinder car will not work on a 3 cylinder one though manufacturers might fit a circuit so it works on both. I fitted an Audi 100 GL car  rev counter into my old Mini as both were 4 cylinder vehicles.
I assume yours will be specific for a 4 Cylinder motor cycle that uses  the wasted spark system - not a distributor

[DomP]

Here's the set up guide.  Mine is an analogue rev counter Ted, I'm thinking of using the wrap around HT lead method of set up to see if that works but I'd rather the hard wired way.  There are no instructions for wrapping around even though a wire is supplied for it

[DomP]

I wonder if this would work

[McCabe-Thiele (Ted)]

The manufacturer of your unit need to employ an accurate translation for their instructions - those are gobbledygook.
My thinking is:-
If one set of points operates  two cylinders with a wasted spark you are getting four signals for one 360 deg of rotation so setting 4 on the left side of the first table (4C-8P).  If its a 4 lobe unit. or is it setting 2 FFS I'm lost already but...

Presumably  if you get the setting wrong it will read either half the true revs or double .
Either way you should get a reading assuming the power supply wiring is polarity correct and earthed.

Update:- I keep changing my mind between setting 2 & 4 either way I cant see why you do not get some sort of output givig a reading

[DomP]

I've tried 2 and I think I've tried 4.  I've got it wired to the black with white tracer coming from the one coil, I think that's correct.

It's terrible isn't it Ted, Koso are a pretty well known manufacturer too!

[McCabe-Thiele (Ted)]

Presumably the unit itself has three connections?
Power and earth to the unit itself  plus the impulse wire that measures the number of  circuit impulses within the unit to translate that into the analogue reading?

I would have thought it ought to be connected to the blue or yellow on the points side - or do the instructions say on B&W side?