Modern Vespa

Looks like the end is near!

I tried the cosa gauge first, and the needle bounced around with the revs like before.

Then I tried the original gauge fitted with the diode, and the needle went to full! (This is the one that had become unresponsive). The needle moves slower than the other (as if with more inertia), but it still moves to the left when twisting the throttle. In the vid below, the needle moves with my pushing the buoy with a screedriver.

I noticed while driving that there's still a nudge to the left when accelerating hard or dropping a gear, but at stable speeds or at idle, the needle seems to stabilize at the right position on the gauge scale.

I call this a win, because it seems to provide a correct reading whenever at idle at a red light or at a stable speed, which is most of the time I check it anyway.

I wonder if, in order to make the needle not react at all to variations in the rev range, a different module could be added to the circuit that would suppress any current value above what idle provides (since the gauge seems to be calibrated for such a value), but without the constant resistance of a resistor. Like a tiny regulator....

Still trying to figure out why variations in revs affect the gauge readings. I checked the regulator in case it was out of whack, but apparently not. Around 9.5 to 10.5V at idle, and up to 12.9 in the high rev range. So seems fine.

Now looking into a way of shaving off the voltage above 10V arriving at the gauge, since that's the range that seems to pull the needle to the left.