Author Topic: Koso gauge RPM set up  (Read 6777 times)

Offline DomP

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Re: Koso gauge RPM set up
« Reply #30 on: September 26, 2024, 08:04:32 PM »
Thanks,  I hope it works finally as I've spent far to much time trying to get it working.  Koso's instructions are absolutely laughable. 
1975 XS650B
1976 CB550F1 current project
2012 Triumph Daytona 675

Offline DomP

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Re: Koso gauge RPM set up
« Reply #31 on: September 28, 2024, 07:33:07 PM »
It works!!!  Thanks everyone for all your help, that's another hurdle overcome.
1975 XS650B
1976 CB550F1 current project
2012 Triumph Daytona 675

Offline McCabe-Thiele (Ted)

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Re: Koso gauge RPM set up
« Reply #32 on: September 28, 2024, 07:53:48 PM »
So how did you connect the wiring to make it work?
Might be worth posting the connections/colours you finally used to get it working for the benefit of others here.
Honda CB400NA Superdream (current money puddle)
Honda CB500 K1 (second money pit)
https://www.sohc.co.uk/index.php/topic,28541.0.html
Honda CB400 four super sport (first money pit)
Link to my full restoration http://www.sohc.co.uk/index.php/topic,23291.0.html
This is a neat 500 restoration in the USA.
http://forums.sohc4.net/index.php/topic,151576.msg1731556.html#msg1731556

Offline K2-K6

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Re: Koso gauge RPM set up
« Reply #33 on: September 28, 2024, 09:10:17 PM »
It works!!!  Thanks everyone for all your help, that's another hurdle overcome.

Well done and nice to get another piece of a jigsaw in place.

Offline DomP

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Re: Koso gauge RPM set up
« Reply #34 on: September 28, 2024, 09:17:14 PM »
It works!!!  Thanks everyone for all your help, that's another hurdle overcome.

Well done and nice to get another piece of a jigsaw in place.

It is, now really just the carbs to get fine tuned, I did a quick float level test with clear aquarium airline and even though I set the floats using Julie's method I've got some running too low and at least one borderline too high.  Carbs off again unless I fiddle around with them in situ
1975 XS650B
1976 CB550F1 current project
2012 Triumph Daytona 675

Offline K2-K6

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Re: Koso gauge RPM set up
« Reply #35 on: September 28, 2024, 09:22:11 PM »
So how did you connect the wiring to make it work?
Might be worth posting the connections/colours you finally used to get it working for the benefit of others here.

Yes, it would be useful info in thread if anyone else then searches for the same .

It should be any one of the yellow wires from alternator windings toward the rectifier Ted. Any of the three would give a "pulse count" to the tachometer if it's equipped to take that input.

I was working with someone on a car and didn't initially realise they did this. It had various input to ecu from electronic ignition etc but with tacho traced back to alternator. Thatt had a winding "tapping" on back of case that came from prior to rectified output post.

Peculiarly, he'd changed the pulley diameter on the alternator such that the rpm was showing different to crank speed  ;D which won't happen on these Honda engines with winding etc  being directly on crankshaft.

That had dome industrial head scratching going on  ;D

Offline DomP

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Re: Koso gauge RPM set up
« Reply #36 on: September 28, 2024, 10:56:14 PM »
So how did you connect the wiring to make it work?
Might be worth posting the connections/colours you finally used to get it working for the benefit of others here.

I'm amazed Koso didn't suggest this in their set up instructions and that it has taken over ten emails to them to get this sorted, it really was as simple as running a wire from the rpm signal wire to any one of the three yellow wires coming from the alternator.  I didn't get an accurate reading straight away but that is adjusted in the gauge menu depending on how many signals you are getting per rotation.

 Instead Koso suggest either wrapping the signal wire ten times around a plug ht lead or connecting to either the blue or yellow wires coming from the points, or in my case Dyna S ignition, the wrap method gave no read whatsoever where as the ignition method gave me a fixed 1000rpm at any rev range.

« Last Edit: September 28, 2024, 10:59:13 PM by DomP »
1975 XS650B
1976 CB550F1 current project
2012 Triumph Daytona 675

 

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