1982 Spectre 1100 Tach issue.

It's a bottom tapped brass insert.




No good access besides disassembly...






View from the side.  Note the needle shaft diameter appears much smaller than the plug in the center back view.


 

KZQ wrote:

I'm thinking that there is a spring bound pivot, for the needle, that needs it's lube renewed.



 

I helped Daveo repair his 160MPH speedo. I don't remember exactly what type of bearings the needle movement used, but I'm pretty sure it did not involve much in they way of lubricant. There is very little friction in the needle movement. I doubt that your issue is caused by old lube or a lack of lube.

When I got the gauge, it was working at low speed, but the needle would stutter and bounce above ~50mph. I initially suspected it was an issue with the electronics, but that was wrong. The issue was that the coil spring that returns the needle is also used as the electrical circuit path to the galvanometer. The fixed end of the coil spring is just soldered to a tab, and the solder joint had broken.  However, the spring was still touching the tab when the needle was near the rest position. As the needle started to sweep, the connection became intermittent and the needle would bounce.

Looking at Daveo's photos, I've circled the tab where the solder joint broke on the gauge I fixed.

 

The trickiest part of servicing the gauge was getting the needle off.  Daveo sent me two gauges so I could compare them.  Before I found the root cause of the problem, I considered just swapping the face plates, since the real goal was to get the 160 MPH gauge working.  The needle on the faulty gauge came off relatively easily, but the needle on the working gauge would not come off the shaft.  Instead, the shaft started to pull out of the galvanometer movement.  It seemed like if I pulled that out, it was never going back in.  And I could not figure out a way to hold the shaft in place and get the needle off, so I gave up on that idea.  Fortunately, as I said, the needle popped right off of the faulty gauge, so I was able to remove the face plate and then get down into the meter movement and find and fix the fault.

daveo wrote: My humble opinion is to avoid all the effort involved, and replace the entire gauge with one known to function properly.

I agree with Daveo that if you can find a replacement part on Ebay, this would definitely be the easiest way to solve the problem.  Having been inside one of these gauges, I'm pretty confident that the only way to fix one is to take the whole thing apart.  If you'd like to try to fix it, I'd be happy to take a swing at it a second time.  But I have never tried to remove the crimp ring.  They were already removed by Daveo when I got them. So maybe he'd volunteer to do that part?  

To remove the needle you have to use two teaspoons to lift it from the shaft.....

 

images.app.goo.gl/2Tkq6y2zwuzaAxt78



 

Scirocco wrote:

To remove the needle you have to use two teaspoons to lift it from the shaft.....
 

Yes. The two screws that hold the face on can be used as lever points to lift the needle. It's not hard to find some small tool to pry the needle up with.
However, if the needle is gripping the shaft harder than the shaft is held into the movement, the needle is going to pull the shaft out with it. I didn't see an easy way to hold the shaft in place.

There's a little pin at the top of the shaft. I broke two off so the next one I made a aluminum cover with a hole and slice in it so I could slip it in under the needle, use a heat gun to warm the the needle enough to pry it off. That's what I use from then on. Came off easy

 

 

Consider Ebay item 395280034847 and similar

Once the cover-cap is removed...


Then


 
Ebay item 145162232857


😉

Sellers provide little detail information, and have even suggested that their tool will not work.  LOL!

...sometimes you just gotta do it yourself.

😏

Wow! A lot of great information here! Maybe make this post a sticky, mods?

I don't think KZQ has an electrical issue. In an earlier reply, they stated that the needle wasn't returning to 0, with the bike off. Though only when cold.
When I disassembled my gauge, the whole shaft came out attached to the back of the needle. That being said, if KZQ attempts this and the shaft *does* come out, it's not super difficult to put back in place once the work is done.
I HIGHLY recommend taking detailed pictures of the gauge before disassembly attempts are made. specifically, where the pin on the upper coil (closest to gauge face) passes through the upper plastic disc (circled in pic). there is a elongated gap here that I suspect is used to control the tension relation between the two coil springs. Also take note of the gap between the wire winding and the ring magnet. 

All of the "drag" on my tach seemed to be coming from where the shaft sits in the metal plate opposite the gage face, in the included picture.

That's a neat little tool!! And puts pressure on the stainless pin where it should be, not distorting the stacked brass e-clips. You don't ever see those E-clips and don't realize You're messing them up using that spoon thingy. The SS shaft that holds the needle has a cut-out land that holds those clips in place and controls endplay. Not exactly sure when the "spoon-removal" technique became popular but it's a BAD BAD idea!! Same as those "Google fella's" that think dino oil is necessary for "lubricating" these gauges. They NEVER used oil but a silicone based grease. 

KeylAmi! wrote:

Wow! A lot of great information here! Maybe make this post a sticky, mods?

I don't think KZQ has an electrical issue. In an earlier reply, they stated that the needle wasn't returning to 0, with the bike off. Though only when cold.

 

Yes I've confirmed that the issue is temperature related. My bikes are generally in a heated space. Yesterday was in the 50s. As I took the bike out of the shop, the tach was working. After about four hours outdoors in the shade the tach would move up and then stick there.

I agree, this thread has the possibility of becoming a resource. I'm following it closely.
Thanks to everyone who has contributed.
Bill

I just randomly responded, didn't realize it was Yours, ha. It's the drag cup fluid. This emollient gets "tacky" over the years and causes this. Temperature sensitive, ya know. And YES this "electric" gauge also has a reservoir, just like every other gauge of this type, that controls sweep. Dampens initial movement and vibration spiking. Sometimes this fluid will seep-out and stick to everything in the vicinity, the needle e-clips, stops if under the faceplate and base of where the drag cup pivots.