the whole stock thing though, i mean, does the stock engine have to be from the same bike? does it have to be a USA model engine (3 xfer 103 or av10,etc?) we all know derbi revo and start motors are a fucking scooter but they run them in 'stock moped' racing.
i think if you're gonna say 'stock' you gotta mean 'a stock moped sold and titled in USA as a moped using its original engine model all original equipment, save for one performance part'
a mbk rcx motor is pretty considerably different from a US model av7, the big loophole all the guys doing stock moped racing use is basically taking derbi scooter parts that are theoretically the same and using them in a stock moped class.
i anticipate a lot of people showing p with 'stock' urban expresses, haha