This thread is a cut and paste from LD rider.
The author has the credentials to know what he is talking about.
I have been too close to lightening too many times on longish rides.
His post is in italics
For twelve years I managed a weather station division at an environmental instrument company that makes professional, sophisticated lightning detection and forecasting equipment. Their equipment is used by the PGA, at all major tournaments; mining companies and the military, where explosives are stored; by schools, during outdoor athletic events. By osmosis, I learned a lot about lightning, and learned to respect it. I've put this warning on the list before. Do not "ride through" a lightning event, if it can be avoided. On a motorcycle it can most certainly kill you, either by striking you, or with an uncontrolled crash. It doesn't need to hit you to incapacitate you. A proximity strike can scramble your nervous system for seconds, or minutes.
I won't go into all of the details because these NOAA link are very good references.
For motorcyclists, get inside a closed structures. If there are no structures, get under a freeway overpass or a covered bridge, go to the center, away from the opening. If none of those exist, you should ride away from the storm. If the hair on your arms starts to rise or itch, or your skin tingles, IMMEDIATELY stop, drop to the ground, and lay flat until the sensation passes or a nearby strike occurs.
Lightning is the second highest weather related killer behind flooding. Ride safe.