Where to take out rpm signal on Agility 200i or similar scooter

[MartyMcFly]

Hi all
I'm thinking about making an rpm counter for my Agility 200, but not sure where to get the tacho signal on such a motor (haven't looked at wiring yet, didn't receive manual yet).
Does anyone know if there's such a signal available from the motor?

For reference, I made one for my old Dax clone as you can see in my video here:

[hypophthalmus]

The cheap tachometer I have for setting the idle speed uses a wire that wraps around the spark plug wire. It uses induction to get a reading.

No idea if that's actually helpful.

[CROSSBOLT]

GREAT SCOTT, Marty! You have done a genious thing with that tach! Hypo is right with the induction idea since the spark discharge is rf or radio frequency even if it is fairly low frequency. Making a pick-up coil should be fairly simple like a few turns around the plug wire, each end connected to your circuit.

Karl

[MartyMcFly]

Thanks for the replies
The wire around the spark plug sounds like a good idea, I'll try it. I just hope the input is high enough impedance.
This rpm-thingy is really just an arduino board with some regulation circuitry and LEDs attached. I sold the Dax but still have the prototype - It might work as is with just the wire
Could be nice to have an idea about the revs the motor does.

[CROSSBOLT]

You may have to ground the end of the wire not connected to your tach to get the signal but try it ungrounded first.

Karl

[hypophthalmus]

If you're willing to release plans of what you come up with, I'd be very interested in trying to duplicate it.

[Stig / Major Tom]

I used a tiny-tach (amazon) with wire wrapped on the plug lead -- seen in photos here....
http://www.kymcoforum.com/index.php?topic=10525.msg107937#msg107937

Two-sided 3-M auto-body foam taped the tach to the body....has been on there for 3 or 4 yrs with no issues. Works fine & records engine hours and most recent ride's high rpm reading.

I positioned it out of direct line of sight - I have found that there is NO time to be looking at the dash for any reason when urban riding! Out on the open road I might give it and the speedo a glance.

Stig