ive went 120 with a bt 80, when runnig away from police
no, a bt 80 engine is just a 4-speed manual gear. more than 50 ccm tomos here in slovenia was never an automatic. but it's easy to get a complete used engine here relative cheap
a new automatic a middle price version costs 200.000 sit (around 900 €)
there are tons of aftermarket parts (mostly used), but u can get new ones too, for a relative low price. it's hard to get a new 70 ccm cilinder, you can get a cilinder "enlarged" if u now what i mean, and put in a bigger piston (i have an '87 automatic with a 40 cilinder)
and putting a 80/90 engine on an automatic is not that rare here
it's not recomended though because of the gears and the "stick that connects piston with the engine" (i dont now the english word...) it is likely to break and destroy the entire engine. but the moped goes like hell