Running an HPI Mini Rotor ignition on my Hobbit and I'm trying to figure out where to hook the wire up for the tachometer. It's supposed to be connected to the positive signal terminal off the coil, but that doesn't exist as far as I can tell.
Thanks all!
Do you have a picture of the Tach you trying to instal?
Trailtech sells an RPM gauge that i am using. You can't see it, but this magnum has HPI ignition. Red wire wraps around the spark-plug wire as seen in photo. Poke the picture and zoom in.
(edited)
tachs either connect to the spark plug lead via induction from X number of wraps around it or to the negative pole of the coil/box.
certain HPI ignitions will also have a “tach out” wire for if you are looking to use a tachometer that doesn’t use a sensor wire.
> Colin Ratcliff wrote:
> -------------------------------------------------------
> Running an HPI Mini Rotor ignition on my Hobbit and I'm trying to figure
> out where to hook the wire up for the tachometer. It's supposed to be
> connected to the positive signal terminal off the coil, but that doesn't
> exist as far as I can tell.
>
> Thanks all!
If there was no positive wire to the coil, you would have no spark. I'm guessing your ignition coil has a single wire plugging into it and grounds through it's mourning point. So the single terminal plugging into the coil is what you would wire it to. You will need to make a small adapter/jumper wire or splice the tach into the wire going into the ignition coil
Thanks all!! Here's the tach I'm trying to install:
Motorcycle Universal Analog Tachometer Gauge LED Backlight Speedometer 0-13000 RPM （Black）
https://www.amazon.com/dp/B081GVKYF8/
Wiring instructions are:
The tachometer has two line groups, which are 2 and 3 respectively. 2 strips are the backlight line of the instrument, regardless of the positive and negative poles, and the positive and negative lines of the illumination line. Three black wires are connected to the positive pole of the power supply, the electric gate is locked to the power output line, and the green wire is connected to the negative pole of the power supply. Yellow is the speed signal line
Looking at more diagrams of similar tachometers it appears it's expecting a signal line. The coil I'm using has the orange line from the cdi, the ground, and the spark plug wire.
Thanks all!
Nick that makes total sense, thank you! Yeah I was a little confused only because somebody was saying it's the positive signal wire "after the cdi" which I'm now realizing probably meant "from the cdi to the coil" rather than "not the one from the cdi"
yea you need the style of HPI that has a tachometer out line.
This guy should work, right?
https://www.treatland.tv/hpi-ignition-coil-with-wire-p/hpi-coil-wire.htm
no, this is what you need.
https://www.hpi.be/item.php?item=210K094A-1CF
the A-1CF denotation means that it has a Tachometer Out line.
That high tension coil you showed won't help you at all and is exactly the same one that comes with any HPI that you buy from Treats or Dos.
Ahhhh dang so I would need to get the new cdi to make this work? Any reason the signal wire to the coil wouldn't do the trick?
it’s gonna be too high of voltage is my guess.
you could try?
> Colin Ratcliff wrote:
> -------------------------------------------------------
> Ahhhh dang so I would need to get the new cdi to make this work? Any
> reason the signal wire to the coil wouldn't do the trick?
The wire going to the coil isn't signal, it's power.
Hooking that up has a high chance of frying your tachometer.
> Dirty30 Dillon wrote:
> -------------------------------------------------------
>
> The wire going to the coil isn't signal, it's power.
>
> Hooking that up has a high chance of frying your tachometer.
he could still try it and let us know
hell it was a cheap tach and it's not getting used anywhere else. Let's give it a go
> Colin Ratcliff wrote:
> -------------------------------------------------------
> hell it was a cheap tach and it's not getting used anywhere else. Let's
> give it a go
Don't hook it to the wire going to the spark plug, hook it to the wire going into the coil and try it
heres the thing i have:
works pretty good. not backlit. my gear ratio just happens to make it easy to also use as a speedometer too as i multiply RPMs by .005 to get MPH
1 == 5mph
2 == 10mph
...
10 == 50mph (edited)
Want to post in this forum? We'd love to have you join the discussion, but first: