Is the RS485 used for anything on the bike in normal operation? If not, I would guess that is more likely to be used for the diagnostic LED codes, presuming the comms lines are used to talk to a display. If the RS485 lines are used for the display, then the comms lines are probably used for the LED codes.
It should be relatively easy to find out which:
--if there is a simple way to cause a harmless error condition (like unplugging the throttle, etc) then a voltmeter (or LED with a 1kohm-10kohm dropping resistor in series with it to prevent overloading either the LED or any commline drivers in the circuit being tested) can be used between ground and each signal line in question, without disconnecting any of the signal lines (either probing from the back of the connector if you can touch the contacts, or poking thru the insulation of the wire itself).
If all you see on the voltmeter is about 2.5v, it's probably an active communications line with serial data passing thru it. On an LED it would appear to be a relatively steady dim glow (dimmer than when connected to 5v, anyway; it migh flicker a little depending on the contents of the datastream).
If you see a fixed voltage on the meter or steady LED on (or off) and you know it is (should be) generating a blink code, then it's probalby just not an active wire.
If you see a changing voltage on the meter (at the rate expected of the blink code), or the blink code on the LED, that's the right wire.
