Please note the lack of a drive chain
Board tack racing, when men were men.
Happy motoring, Warren
Wonder how much lumber was used for a track and how long they lasted.
Most of the board track racers did not have a clutch or gearbox, they were pushed or pulled to get them started and the race was started with a rolling start after a lap.
The chain was no doubt removed to ease moving the bike around for photographs.
Replacing the 2X4 boards so often was one of the reasons board tracks were abandoned, that and a bad accident.
That looks like Charles Lindbergh.
Lindbergh was born in 1902 and would have been a bit young to drive during the board racing heydays before the US entry in WW1. He did drive a 1920 Excelcior "X" twin, though, bought at Martin Engstrom's hardware store in Little Falls, MN in 1919. He kept it until 1943 & donated it to the Henry Ford museum.
Here's a young Lindbergh on his bike besides an unknown Ford speedster: