Z1 gauge damper

I took apart a 73 Z1 tach because it had needle bounce. Anyone know what fluid or light self leveling fluid was used?  I tried using an NGL #1 grease which works but I'm sure isn't right. After seeing the design it looks like there is no seal on top of the damper. A good reason to never store any of your gauges on its face because the fluid will migrate out. Also looking for source for the seal. Bob used to work on all my instruments but sadly is is no longer with us. Any help appreciated.

Differential fluid 100k vis is what most of us use. You can find it at your local RC racing center or on line.  The brand I use is JTP. there is a whole write up here on gages. Might want to try a search. I drill a small hole and use a needle to fill the cavity. I seal id with a small piece of Aluminum tape and coat the edges with super glue. 

Yeperra, Good Morning! They had 3 different drive mechanisms used in the production of the True Z (72-75) and had different fluid cups. Earliest being a "bullet" type. second had a glued-on cap and last a clear rubber cap that you could lift off. You say needle bounce. Yes, this can be attributed damper fluid loss but can also be needle "spike" which can be mechanical. If you can grab the flared bell that rides over the top of the spinning magnet and move it back and forth then the cast hole where the Stainless steel pin goes into is worn out. This worn casting hole allows the inside of the bell to wander further then closer to spinning magnet causing erratic needle movement. Too worn and it'll actually contact the spinning magnet which will result in sporadic "spiking" of the needle. Just recently had the day off lounging and watched a handful of the DIY fellas take on various motorcycle gauge "restorations" on Youtube. WoW..such incorrect information, blind leading the super blind, ha. Carb cleaner and 3-in-1 oil "lubricating" oil abound. You DON'T lubricate these mechanical mechanisms of this type, just makes a mess. As you've probably already found, grease is the incorrect product for damper refilling, it has the incorrect properties and does nothing but also just makes a mess. Any hoot, what's the face of gauge look like, cracked/distressed? Whoops, just noticed You'd sent me a PM! I'll contact You today and provide more info pertaining to these then you'd ever wanted to know, ha Clay       

Yes the lower casting can be worn. I have found one of my gages with a very worn casting. I was able to make a brass bushing for it. Clay has other methods. Lots to learn when servicing these old gages.

Thanks to everyone who replied. I'll get the Diff 100k and see how it works. Thanks for that Cra-z1. I'm new to these gauges so I decided to use this one as learning tool. The one I have has the snap cap on it so it's easy to take apart and clean the grease I put in. I'll use the 100k stuff this time around. I'll keep you all posted. Thanks to Clay for taking time to call me. He gave a lot of good advice which I needed!
Yon

While i'm fiddle-farting around with a couple sets of Z1 gauges, i took some pictures while everything is apart. Might get a better understanding of common issues with these and why they misbehave. This chronicle will explore "why is my gauge spiking erratically". The cast hole for needle shaft support is worn out on this one so it's a prime example, photos of understanding provided. When the cast hole is badly worn "enlarged" the drag cup will rub not only on the half tin bit shown but also on the lower cast support that has that hole for support. Note these shafts are NOT end-play controlled by this casting but by a couple E-Clip brass stacked and sandwiched up top. That's why i deplore the "spoon pointer removal" technique often touted, you distort these tiny little clips. Anyway, note the blue arrows and witness mark left on that half shield. Good Luck!          

Clay that one is very worn. Here is my fix on one
 

Looking Great Grasshopper!! I do similar if time allows relieving the 4 metal bendovers on the upper carrier/control plate. Crazy don't know You've ever fiddled with the Kawasaki Triple gauges but they (Nippon Seiki) were built with a brass lower bit already installed. Unlike the Z/KZ Nippon Denso units this lower actually WAS part of the (End-Play) control. You adjusted a sleeve and locknut up top underneath the needle to set it. Much easier, just remove one Phillips screw and lower carrier comes right off! Didn't Wookie start some sort of "file" pertaining to this type of stuff for you Crazy?   

It’s in my “to do” list:)