Analogue Tachometer

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nellyboyo
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Just tried a single cylinder analogue tacho which I picked up cheap and I like a bit of a play about if you know what i mean .
I wired up to the green wire and earth ( only 2 wires ) and It works but is way too sensitive .( read 2k at tickover and off scale when revving )
So I wired a 33 ohm resister in series which improved it a bit . Then tried putting an electrolytic capacitor in paralell which didnt work . I don`t have a decade box so is it just a suck it and see with some larger resistors in series ?
It is scaled correctly ( ie 1000s )

Anyone great with electronics ?
cheers
nellyboyo
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No One ?? ;)
Grumpy225
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nellyboyo wrote:No One ?? ;)

More information is needed.

Make and model of the unit would help a lot. You might be able to find a proper set up diagram online for it.
nellyboyo
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Image
nellyboyo
registered user
Posts: 325
Joined: Wed Sep 22, 2010 10:28 am
Main scooter: Lambretta
Contact:

Image
nellyboyo
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Joined: Wed Sep 22, 2010 10:28 am
Main scooter: Lambretta
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Sorry boys had a bit of technical error there, can any mod delete the rubbish posts please ?.
Anyway . I think its off a microlight . I took the black wire to earth and used strapped the red to the green on the CDI , As I said it worked but was way too sensitive .
Its a great size so if I could make it work I`ll mount it as it looks spot on.
hendy
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It sounds to me as if it's reading double. This could be caused by two things that I can think of:

You have a varitronic ignition. This generates 2 pulses per revolution.

The tachometer you've got is for a four stroke, which by its nature revolves twice for every ignition stroke. This may mean that it's configured to read 2rpm for every pulse.

Either of these would mean reconfiguring the unit rather than adding external components.

I hope I'm wrong, but obviously I don't think I am or I wouldn't have said it. :-)

Good luck.
nellyboyo
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Joined: Wed Sep 22, 2010 10:28 am
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Ha, no I don`t have varitronic and I don`t think it is reading double as it will only go up to around 7k revs with a big handful .
It just gets there way to quickly .
It was sold a for a single cylinder 2 stroke but its not the end of the world if I can`t get it to work some shape .
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