Ok, thanks for the additional clarification. I get it now. The Hella turn signal relay has a turn signal indicator bulb connection for fast flashing when a turn signal bulb is burnt out. Connecting the black/white to the green/yellow should make the indicator bulb operate normally.
I was reading the instructions about momentary switches, then misread the wiring diagram and got confused. On an airhead, the turn signal switch must be kept in place for however long the flasher is flashing. I don't think it makes any difference if an LED is used in place of the standard indicator bulb.
Edit: well... maybe not, based on the expanded explanation below.
Stan_R80/7 screwed with this post 12-15-2012 at 12:58 PM
Reason: Changed the post