So it turns out that even though my bike didn't come with an oil pressure switch (it's a 2008 model), the speedo does have one built in ready to use. After comparing the electrical schematic for the later bikes with those for my machine, I found that every connection to the speedometer is the same, except the later bikes have pin 14 connected to a normally closed oil pressure switch which then grounds through the engine. NB: the drawings actually show a normally open switch, but they are wrong Of course now I had to install a pressure switch. I got lucky and found a used one, including the hose and oil filter cover on ebay for $7. The hardest part was finding out who was the OEM for the oil pressure switch electrical connector. After a mere 4 hours of googling I found that it's made by Yazaki. If anyone want's to copy me the part numbers for the speedo pins / oil pressure switch connector are: Speedo: JST SXA-01T-P0.6 pin for the speedo plug (https://uk.farnell.com/jst-japan-so...-p0-6/crimp-socket-xa-24-20awg-tin/dp/1830863) Oil Switch: Yazaki RH 7283-8851-30 connector set (https://www.automotiveconnectors.com/2-way-yazaki-rh-connector-female.html) For completeness here's my pinout for the speedometer. Pins 19-21 aren't listed in the KTM drawings, but function as remote buttons for the trip meter when grounded, allowing you to cycle through the different trip meters and adjust trip 2 up or down.