hey thatonedeadguy, what a coincidence. i just came in the house from test riding my 1966 s-65 that i just put a 110cc motor on today.
wow!! that thing is low geared. looks like we're in the same boat. i'm a 200 pounder, and i can easily start out in 3rd gear. i've done a little searching and came up with this:
http://www.hooperimports.com/product.aspx?pf_id=420-125cc
it's a 17 tooth 420 front sprocket. they also have 'em in a 428.
on your brake pedal, i think a pedal from a honda c200 might work, it has a low pipe from the factory.

oh and, what did you do with your air cleaner connection, i'm kinda stumped.