Here's an instructable from a guy converting his old 6v bike to LED lights.
And this guy is converting his old analog flasher to a new digital timer that will work with the low current draw of LEDs.
I remember reading a project where a guy converted his bike from the old conventional bulbs to big 4" diameter LED arrays, that was my favorite and of course now that I want to show it to someone, I can't find it. But that was what I thought a proper taillight should be on a motorcycle, vast. In E. TN it appears to me that if you aren't at least a car, a lot of drivers would just as soon mow you down.