Wagging Fuel Gauge Level

[Donkey Hotey]

Okay, this is a new one. While out riding 1525 the other day, I glanced down to see the fuel gauge wagging wildly all over the range (had about a half-tank of actual fuel). I figured it must have a bad connection somewhere. After stopping, the flapping slowed and seemed to match the fuel sloshing in the tank. As the fuel settled, so did the gauge.

I just pulled that gauge cluster apart and removed the fuel gauge. It freely spins with no soft damping at all. I have no idea why this would happen all of a sudden. I'm pretty sure there is a damping fluid they put on these mechanisms to give them that smooth, slow response.

Has anybody else had similar issues with theirs? How did you fix it?

Thanks,

[Donkey Hotey]

Answering my own question here: after doing some online research, the product I'm looking for is damping fluid. It's the same stuff they use to make old turntables have smooth tonearm movement and give certain switches and controls that nice, soft, fluid feel.

At first glance the fluid might look like a thick grease but, it's function is not to lubricate. Damping fluid is designed to have a high-shearing behavior that slows things down or puts drag on them.

Apparently it's not uncommon for the stuff to run out of the joint where the fluid was used. It's also allegedly not difficult to drip some more back into the pivot to restore the smooth action. I have ordered some silicone damping fluid that is designed for the differentials on RC cars. I saw it recommended elsewhere for car gauges. I'll report back what I find when it arrives.

[wytfut]

Wow Greg...
This is a whole new science for me..
I had no idea.

I read your post when it first came up. And the only thing I had to relate was that my fuel gauge had bobbed a couple of times on cold starts.

This is drawing my interest

[Donkey Hotey]

The bottle of 100,000 CST silicone damping fluid showed up. Now it's a matter of trying to get it down into the pivot on the gauge. Being thick, it doesn't exactly want to run down the center of the gauge shaft.

I took a small screwdriver with some on the tip, dabbed it around the shaft (from the side of the gauge) and tried to tamp it down into the joint. It's better but, not fixed.

I'll give it a few weeks with that in there and see if it eventually seeps down into the pivot or if disassembly and a syringe is going to be necessary.

[wytfut]

Sounds like that is going to be one big bore syringe.