How to calibrate a tachometer.....
Well, see my website and there is a manual on calibration of speedos, and the
tach is similar.
In a nutshell, either the pointer is pointing too low. This is evidenced by a
fairly constant error all the way thru the RPM range. I.E. it is always
about 800 rpm low. If so, then you need to twist the pointer to the proper
location. Hold the drag cup with the pointer at 1700, then gently twist the
pointer to 2500. Now it will read 2500 when it used to read 1700.
If the error is not constant, then the amount of drag created by the drag cup
us inadequate. Some extra magnetism (just a little extra) will move the
pointer more. Again, see the manual for this info.
Tony Rhodes
http://mywebpages.comcast.net/rhodes/
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