Throw a couple of ropes or some tie downs over a strong cross beam in your Granpa's shed or barn and attach one one each side of the back of the moped and attach a rope or tie down to each side of the front of the moped. This is so you can lift the frame away from the subframe.
Tie downs work best becuase you can raise and lower them using the mechanism on the tie downs.
Disconnect the rear brake cable from the rear wheel.
Now remove the rear bottom shock bolts on each side of the moped. Remove the one big front bolt in front of the engine area that secures the frame to the sub frame
Now use the tie down or ropes to lift the frame away from the subframe and disconnect the throttle cable from the carb and the wire from the coil to the wiring harness. Be sure and note where all the wires are plugged in so you can put them back in the correct places.
You should now have easy access to the carb.
You will need some penetrating oil and a hand held impact wrench to wack the four phillips head screws that hold the carb to the manifold. It is very difficult to get the screws out without first wacking them to break them loose.
Once you have the carb out, the reed valve is underneath the carb, remove it and inspect it to make sure the reeds are flat and in place and not bent.