Excelsior twin.

Indian and Excelsior wall of death bikes.

Excelsior race and street bikes.

Pete and his Excelsior.

Excelsior twin.

Street scenes with early motorcycles.

Tell the guy on the right to put down his cellphone! 

Miss Kitty photography.

Miss Kitty.

1910 Boston show.

1909 Chicago automobile, motorcycle and boat show.

Excelsior Auto Cycles.

Excelsior Auto Cycle.

Excelsior motorcycle.

Reynolds North Dakota MC.

Excelsior race bike.

Excelsior single with belt drive

Excelsior motorcycle.

Amazing group of photos taken June 9th 1914 in Toledo Ohio.

Merkel teammates with Jones at the center. 

Bill Goudy in his leather helmet.

Merkel rider Cleo Pineau?

I believe the two above pictures are of  Maldwyn Jones.

These photos were taken at a somewhat pivotal time in the industry.  One month after this event Harley Davidson entered its first factory race team in the Dodge city 300.  One year later in December Yale quit making motorcycles.  This was also one day after Charles "Fearless" Balke was killed practicing on a Chicago area dirt track.  The event pictured here was won by Lee Taylor on a Indian.  Balke was his team mate.