I don't usually post on forums, but I'm at a loss as of now.

I bought a '97 F3 recently and a few rides in I noticed the tach was shaking a little bit at top end but didnt think much of it. A couple rides after that it had gotten way worse. At the low end of both the tach and speedo the needles are smooth as butter, but the higher the needles climb the worse it gets until at about 75+mph and 9k+rpm the gauges are going so crazy that theyre useless.

So far I've:
-Replaced the regulator/rectifier (noticed plug was burnt)
-Replaced the stator (this plug also looked slightly crispy)
-Took the cluster apart and checked continuity on the printed circuit and cleaned it before reassembly
-Checked the entire wiring harness from the cluster back

As far as I can tell the only thing I havent done is replace the gauge cluster. I thought id post here first before dropping even more money on a potential fix in case anyone else notices im overlooking something. Thanks guys.

 

Measure voltage going into cluster using power & ground wires at cluster connector itself.

Measure resistance between cluster's ground wire and chassis ground. ohms = ???

This is electrical problem, not bad parts problem. Replacing perfectly-working parts with brand-new perfectly-working parts won't change anything because actual problem hasn't been positively identified. This is 5-minute fix with multimeter, or less in many cases...

 

Thank you for the reply.

Power into cluster: 13v
Cluster ground to chassis: 0 ohms

 

Update: I found a 95'-96' F3 service manual and followed all the steps for troubleshooting both the tach and speedo to no avail but the wiring is a little different for the '97 so theres a few steps that I just did to the best of my abilities.

Does anyone have a '97 service manual?? I can't find one for the life of me. All the links ive found on forums are old and broken.

Also, heres a short video of the gauges for anyone interested.

 

There is a pdf version in the sticky section of the f3 forum.

 

Thanks, but thats where I got mine. I'm assuming its the '95-'96 manual because the wiring is different than mine as well as some of the sensor locations.

 

It’s for the entire f3 generation. With the exception of the noted differences, it should all be the same. I have a ‘98 and used it to troubleshoot my cluster and it’s accurate in that regard.
is it possible that your bike is an f2?

 

Nope, its definitely a '97. The wiring diagram shows completely different colored wires on the cluster connectors no matter which diagram I look at.

You mentioned youve troubleshooted the cluster using the manual before. When measuring the voltage at the cluster the manual states you should have "battery voltage" but im reading ~0.5v less at the cluster than at the battery. Do you know if this is close enough to battery voltage or if it indicates a problem?

Also, measuring cluster ground to chassis shows 0ohms perfect continuity until I turn the key on, then it jumps to ~120ohms. Service manual says nothing about this measurement.

Thanks in advance.

 

Welp, its solved for now. As long as I dont tighten down the bolts that hold the cluster to the bike then they dont shake at all. There must be something just loose enough inside the cluster that the vibration from the bike sends it haywire.

I tightened the clusters bolts just enough for the rubber grommets to barely contact the frame and then tightened a nut onto the back of them so they cant come loose, that way the cluster is basically floating on those rubber grommets. The needles are smooth as butter now...

 

That’s great news.
Sorry I didn’t get your answer back to you.
when I worked on my cluster it was about six years ago. I don’t remember the details of the values.