The biggest meanest kit out there for Sachs 504 and 505. 48mm, 80cc cylinder kit by Athena. Really, it is one of the meanest kits for any moped. Hope your clutch can handle it!
Comes with an SHA and a PHBG intake. Single ring piston. Neat exhaust flange as well.
Includes cylinder, piston, ring, pin/clips, gaskets, reed valve, 2 intakes, and an assortment of hardware.