From the RTV1100 2009 Service Manual.
Hi Guys,
From the old manual it was R/W (red/white) for the radio feed and
B (black) for ground.
The R/W wire looks like a common power feed for other items as well so would be good for your radio if you can find one in the location where you will install the radio.
Any B wire will work for ground or a simple screw into anything metal in the area would probably work as well.
Test with a test-light to see if R/W is live with key on/off, to verify.
Companies don't often change the color of wires between years and models, so I suspect most of the colors are the same as the older models.
Good Luck.