What would be easier to do, but not as accurate would be to calculate the weight of ~4 gal of gasoline and 3 qt of oil.
Than add that number to the advertised dry weight of any motorcycle.
I wonder what the average wet wieght that you have listed minus the advertised dry wieght would be. I'm figuring that these two methods would produce a similar number.
Danger is one thing. But danger plus extreme discomfort for long periods is quite another.