Jeff, I think I understand your situation: At low RPMs the pointer is
close to correct, but
reads too high at higher RPMs, and the error increases as the RPM
increases.
If this is correct, it is not caused by binding of the pointer needle which
would give a falsely _low_
reading.
It is not caused by poor lubrication of the input shaft.
It is probably caused by a loss of spring tension in the coiled return
spring (hair spring).
This is adjustable, but would be a real pain of
unsolder-tighten-resolder-test sequences
until the reading was correct throughout the range. It might be better to
send it out to be
recalibrated by the pros.
I have a speedometer repair manual (tachometers are similar) at
http://ourworld.compuserve.com/homepages/arhodes
let me know if I can be of more help.
-Tony
Message text written by INTERNET:triumphs-owner@autox.team.net
>From: "Jeff McNeal" <jmcneal@ohms.com>
Subject: Tachometer calibration anyone?
Hello all, just as I suspected, my tachometer is out of whack. It was
showing 4,000 RPM at 55 mph, which is around 500-600 RPMs higher than it
should be reading. I connected an electronic tach this evening and sure
enough, at lower RPM's, my reading is off by a small amount, but as the
RPMs
increase, the error grows commensurately. At 4,000 RPM on the electronic
tach, I'm reading about 4,500 on the mechanical Jaeger. I wouldn't mind
trying my hand at calibrating the thing myself if such a thing is even
possible. Has anyone done this?
best wishes,
Jeff in San Diego
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