Topic: Tachometer Accuracy? 72 CB500

[b52bombardier1]

Hello,

  I have tried three different dwell tachs plus one of those inductive pickup tachometers from Pit Posse and they all seem to indicate that my bike tachometer is indicating about 500 rpm high.  This makes it tough to accurately set the rpm with the bike tachometer. These dwell tachs do indicate that I'm good on dwell angle at around 45-47 degrees.

  OTOH, my calibrated eardrum is telling me that the bike is idling too fast when I set the idle screw to around 1000 rpm on these supplemental rpm gauges.

   Anybody else found that these bike tachometers are a little off?

Many thanks,

Rick

[Deltarider]

All depends on the cyl scale you choose. Since we have a wasted spark ignition sometimes you have to multiply (or divide) what you read by two. Try again and please report back.

[b52bombardier1]

I had not thought of our "wasted spark" form of ignition.  However, these dwell tachs all either have a four cylinder scale for reading the values or guidance to double the readings on the eight cylinder scale.  One of these dwell tachs even has a calibration routine that I have ran so I have some confidence that its at least in the ball park accurate.

More to follow later this weekend and thanks for your advice.

Rick