Originally Posted by JRWooden
Could it be your radiator cooling fan kicking?
That would probably temporarily drop the voltage down to that range as it came up to speed...
That certainly fits with the symptoms and is something easily tested by toggling the fan and watching the voltage.
However, when I noticed it on the road, I was riding at highway speeds on a relatively cool day and I would be surprised if the fan kicked on at all since even idling on a hot day takes several minutes to activate the fan.
Now the geek side of me wants to put a little indicator lamp on the fan circuit.