Not sure about your blinking light, but a few years ago I had the same symptoms on my 87 GL "Long John."  A normal round of short blinks at startup, and then afterward a non-stop blinking situation.  If I turned the ignition off and then back on, sometimes it would go back out.  However, it was not long afterward that I was driving around in Westcliff, CO, and blew a headgasket.  As it turned out, the fan or fan switch (can't remember now) was defective and the engine overheated.

I was never sure whether the blinking light and the blown head gasket were related, but after I had the head gasket repaired I also changed the fan, the switch, and the radiator and the problem never came recurred.

The (possible) moral of the story: don't ignore those blinking lights!

Warren L.
88 Westy 2.2 "Billy Bones"