Tachometer Woes!

[jml]

Hey all,

I've installed a Tachometer [Hardline Hour/Tach] onto my Beta but the RPM it's showing is way off. When I touch the wire in any mode (near the spark plug end) with my fingers it drops by a factor of x2. Am I missing something? It's an induction type that just wraps around the spark plug lead.

The tach supports the following modes:

• 1 pulse = 1 revolution
  
• 2 pulses = 1 revolution
  
• 1 pulse = 2 revolutions
  

RPM shown in the following mode:

• 1 pulse = 1 revolution (4000rpm)
  
• 2 pulses = 1 revolution (2000rpm) (drops to 1000 rpm, when wires are touched)
  
• 1 pulse = 2 revolutions (8000rpm)
  

Any ideas? If you are currently using a tach/hour meter with great success what brand/mode?

Thanks!

Edited June 21, 2014 by jml

[lineaway]

Some how I doubt you will get much feedback. Not a trials thing to do, but good luck.

[jml]

Some how I doubt you will get much feedback. Not a trials thing to do, but good luck.

Looking at the tach more for setting idle RPM, not really worried about anything else

[dan williams]

Yeah not a typical trials thing to do. Usual idle adjust is;

Are you stalling in sections? Turn idle up.

Does the vibration when you're sitting in line waiting to ride a section tickle your gentleman bits? Turn idle down.

Two stroke dirt bikes are notoriously unpredictable with inductive pickups. One other thing I've noticed on the beta flywheel is two trigger magnets 180 degrees apart. Whether this causes the ignition to fire twice or just serves to ping the microcontroller in the CDI with a timing signal to set advance I don't know.