oberonspacefr...
Nova Slayer
Joined: 17 Dec 2015
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 Posted: 12:11 - 10 Feb 2016  Post subject: Wiring a tachometer (in dash unit) what does it connect to? |
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ive spent quite a while on youtube now, and i have a general gist, but i thought id check opinions on here.
the tach is part of a new koso type digital dash.
there are no instructions, other than to tell you which wire should act as the feed for the tach.
YOUTUBE says 3 things
1. wrap it around the spark plug cable, and tie it off (wierd)
2. attatch it to the live output of the coil
3. bizzarely, id have thought, attatch it to the negative of the coil.
i must surely be missundertanding no 3 as thats just an earth to the frame isnt it?
Id happilly try all three, but i dont want to burn a new dash unit out fooking about so im collecting opinions as to which to try.
next will be the temp..........  im guessing thats a lead from the engine as its air cooled? I may just leave that option off..... |
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chris-red
Have you considered a TDM?
Joined: 21 Sep 2005
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Pete.
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Joined: 22 Aug 2006
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| Posted: 14:01 - 10 Feb 2016 Post subject: Re: Wiring a tachometer (in dash unit) what does it connect |
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| oberonspacefruit wrote: | ive spent quite a while on youtube now, and i have a general gist, but i thought id check opinions on here.
the tach is part of a new koso type digital dash.
there are no instructions, other than to tell you which wire should act as the feed for the tach.
YOUTUBE says 3 things
1. wrap it around the spark plug cable, and tie it off (wierd) |
Yep, can work. You're making a coil and it will (might) pick up the pulse of the spark as it passes down the lead. Safe to try at least just keep the bare end away from the plug lead ends. The more turns you get round the plug lead, and the tighter you make them the better.
| Quote: | 2. attatch it to the live output of the coil |
Again, might work won't do any harm to try. The 12v input will theoretically never change but in reality when the coil is re-energised after the spark fires there will be a drop.
| Quote: | 3. bizzarely, id have thought, attatch it to the negative of the coil. I must surely be missundertanding no 3 as thats just an earth to the frame isnt it?
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Nope, it depends on the ignition system where it goes but it'll never be direct to earth unless it's a lawnmower. This is probably the most likely place you'll find a tach signal actually. No harm to be done by trying.
| Quote: | Id happilly try all three, but i dont want to burn a new dash unit out fooking about so im collecting opinions as to which to try.
next will be the temp.......... im guessing thats a lead from the engine as its air cooled? I may just leave that option off..... |
As Chris said, air-cooled don't usually have temp sensors. You could fit in the fins with high-temperature epoxy or something but you'd have to cobble up a driving circuit and even then would it tell you anything meaningful?
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a.k.a 'Geri'
132.9mph off and walked away. Gear is good, gear is good, gear is very very good  |
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oberonspacefr...
Nova Slayer
Joined: 17 Dec 2015
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| Posted: 15:22 - 10 Feb 2016 Post subject: |
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nope, your right. its got a wire for it, so i was going to try and wire it all without really thinking. i wouldnt know if 180 degrees was good or bad-as you say no need really.
somtimes you have to pause for though dont you..... 
ill try the ground first, as that seems safest. |
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