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Tachometer Bouncey

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J

Jimmy74

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Hey guys:

When changing thru the gears my tach kind of overshoots the actual rpm by about 500 rpm, falls back about 500 under actual rpm, then overshoots by about 250 rpm, then undershoots about 250 rpm and wags back and forth (under/over) until it settles at the tru rpm. Blip the throttle and it happens all over again. Bouncey you know? Anyone got any ideas?

Clutch, tranny and drivetrain aren't the issue, it's the tach. I've removed it during the rebuild and may have re-wired it wrong on installation. Thanks.
 
There will always be some degree of "bounce" in the tach, since it's just a magnetically operated, analog electrical meter. What you describe might well be excessive, though. If there is something wrong, about the only possible place is in the electronics, and it could be (as in the link, above) bad capacitors. The electrolytic capacitors tend to deteriorate over time.

They're easy to replace, just unsolder the existing ones and solder in a new one. Ones available today are much smaller that the older ones, and they use standard values that haven't changed over the years, so for sure you can find one that fits. Be sure to observe polarity. If you're not familiar with working on electronic components it might be a good idea to let someone else do it.
 
Make sure the tach has a good ground too.
 
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