Sluggish Tachometer

[Rikugun]

I've got two tachs from RJ's that function but seem to react slowly and/or don't fully return to zero when the engine is turned off. Any thoughts?

[QBS]

Never been into one of our tach's, but your problem description sounds like a mechanical internal need of lubrication issue.  Perhaps a bearing or bushing that carries the needle.

[Walt_M.]

I opened mine up a very long time ago, it was inop, had an open coil. Which I soldered. It is still working as of yesterday. Is there a spider or insect in there?

[fret not]

Never store your speedo or tach with the face down.  There is a small reservoir of oil that is used as a damper for the needle and it can leak if improperly stored.

[Rikugun]

Thanks for the input guys. After posting I found this discussion with a very similar issue: http://ridersofvision.net/rovforum/index.php?topic=15605.0 Some questioned the TCI but I have a sense it's a lubrication issue as mentioned in this post. I have a spare TCI I can try just to see what effect if any it has the next time I'm in the shop.

Never store your speedo or tach with the face down.  There is a small reservoir of oil that is used as a damper for the needle and it can leak if improperly stored.

That's a new one on me FN, thanks for the tip. It does fit the symptoms. I have a set from a crashed bike I may tear apart. There will be no pressure to get it back together correctly as it's fairly beat up but will shed some light on the internal workings without disturbing a "good" set of gages.

[fret not]

When I worked at a dealership in the 70s I was chastised by the manager for putting a speedo on the shelf with the face down.  He showed me a tach with some oil on the dial because it had been stored face down.  It takes a while for the oil to leak out.