Hi Lynn,
I'm sorry you seem a bit unhappy about dating the Yale motorcycles in your photos at 1910, even if I can understand your scepticism of information that arrives via the internet! I'll attach period (and dated) illustrations of the 1906 and 1910 Yale models to show the differences. For more info (for example to show that the 1909 Yale is quite unlike the 1910 model), follow the link in my previous post above.
I'm not an expert on Yale, but I am very interested in the origin of the Yale motorcycle as I own a 1903 California which was the basis for the 1904 "Yale-California" - the first Yale motorcycle. Or at least what I thought was the first Yale motorcycle! I'd be most interested to hear more about the 1901 Yale Test, as I've not heard of it before.
Cheers,
Leon