Calibration is complete and the speedo has returned to normal operation. Depending on your recalibration needs, the pushbutton can be removed or mounted under the dash for easy access.

If you have either an internal or external coil magneto and want to install one of our products onto it (tach, shift light, Pro-Control or another device), it is not difficult in most cases. However, when you connect ANY electrical device near a magneto you MUST realize that mags produce tremendous amounts of RFI (radio frequency interference) that can play havoc with any of these devices.

One of the easiest ways to understand what RFI is or what it does is to watch TV.? If you have ever been watching television and someone is running an electrical motorized device (a vacuum, for instance) usually you will see lines or some other form of distortion on the screen.This is similar to the interference that the device you are using is picking up from the mag, and the reason you see the incorrect operation of the unit you are working with.

Our products are compatible with most of the mags in use today; however, we see more problems with the external coil mags rather than with the internal coil mags. Also, when you run a mag, most manufacturers insist on using SOLID CORE plug wires that DO NOT have radio frequency suppression. This means they act just like a radio antenna; each individual plug wire "broadcasts" the ignition firing.

When the engine is running at low RPM there isn't a very strong signal, or a high frequency of the ignition firing. Also, at idle, there isn't much of a load induced on the motor, so the electrical system is at a normal level. However, when you raise the RPM, thus raising the frequency in which the ignition fires, and the voltage as well, the signal gets stronger and stronger. Instead of the one signal that the RPM device should be receiving, it is being bombarded with all this extra noise". Because of this:

A tach can display a higher RPM than is
   actually being turned.
A shift light can come on earlier than it
The Pro-Control can start to rev limit
  earlier than it should.

The mag causes all of this because of t ' he incredible amount of power it produces; this interference is its by-product.
What is happening is the device you're attempting to use isseeing more than one engine RPM signal.
What can be done to correct this problem?
Well, there are a few different ideas, and usually the culmination of all efforts combined yields the best results.

Ground both of the cylinder heads to the
  frame or the negative side of the battery.

Ground the mounting strap or band clamp
  for the mag mount.This will help to direct
  a large part of the "noise" direct to

We have found that changing the plug
  to wires that have RFI (radio frequency
  interference) or EMI (electromagnetic
  interference) suppression work well in
  holding the signal inside the plug wire.
Route the power and ground wiring for
  the device you are installing away from
  ANY of the ignition components (these
  wires can "soak" up the extra signals).
  Usually the further away your components
  are from the engine bay and specifically
  the mag, the better off you'll be. This
  larger distance usually works because the
  intensity of the signal drops as the
  distance between them increases.
You can also insulate the power, ground
  and signal wiring by slipping braided
  wire shield (with a known good engine
  or chassis ground) over the wires. This
  will help isolate the signal so the device
  you are using receives only one signal
  rather than the multiple signals it could 
  potentially "absorb" from the magneto.

Which is better for monitoring a vehicle's electrical system: a Voltmeter or an Ammeter?
Short answer: A voltmeter, by far.

Mark Hamilton of M.A.D. Enterprises
points out that amperage is a measure of
current flow, so an ammeter is actually a
"flow meter" that's intended to measure
current flow to the battery (under normal
conditions) or discharge from the battery
(in the case of alternator system failure).
On a typical flow meter, all output must be
directed through the device to obtain an
accurate reading. In the ammeter's case,
that means all the alternator output used to
recharge the battery must first be routed
through the ammeter under the dash. This
requires a heavy-gauge cable and presents
a possible fire hazard if not installed
perfectly. The ammeter itself must be able
to handle all this current flow, so it must
have a higher current rating than the
alternator's maximum rated output.