Hi folks, I have a Tom Tom 40 Rider, can I use the 4.5 accessory connection on my xdiavel for power,

Hi
Yes, the Rider 40 Mount connects to a 12-Volt supply....
Rider 40... User Guide....
Here... https://download.tomtom.com/open/manuals/rider_400_40/refman/TomTom-Rider-EU-RG-en-gb.pdf
Page 10.... Important: The red POS (+) contact needs to be connected to the motorcycle's wiring loom at
a point between the ignition and the +12V battery supply. The black NEG (-) wire needs to be
connected to the motorcycle's wiring loom at a point between the ignition and the -(GND)
battery supply. Attach to a 12V point that can be switched off by the ignition such as the light
circuit.

Stay Safe... ATB YFM