Remove the transmission cover on the left-hand side of your moped, using a screwdriver.
Put the transmission cover and screws somewhere safe.
Use an impact wrench to remove the nut holding the variator -- the windmill-like metal wheel located on the left of the open transmission -- in place. Take the variator out and look for a washer preventing the two halves of the variator connecting.
Unscrew the two halves of the variator, remove the washer and screw the halves back together. The washer prevented your moped from reaching its top speed, which it will now be able to do.
Put the variator back into the moped and fix into place with the nut. Screw the transmission cover back into place and you are good to go. Removing the washer can boost your moped's speed by up to 20 mph.
