Hi
Last week I was afflicted with a nasty case of wobbly speedo. I used the search feature on this site to find that a whole bunch of others had also been suffering from this tragic disease.
Anyway, having a fair amount of dealings with speed sensors on other applications, I noticed this was a common failure for most speed/position sensors.
Kymco have been nice enough to re-engineer the replacement as they presumably had so many fail.
The new part number for said item is: 31340-LBA2-E0A
I hope this helps someone out, the speed sensor is always going to be the most likely failure mode between the wheel and display.
It's not a cheap fix $66 (ish) plus shipping & taxes, but a lot cheaper than the speedo cluster.
Unfortunately the old one is pretty much un-serviceable, the wires are 'potted' into the sensor, so gently scraping and chisseling may get to the pins to enable re-soldering a new cable, but unlikely.