Primary chain covers for Singles and 750es

Smaller Harleys (single cylinder models A and B, 750 cc twins series D, R, W, and G to name the most common) had pressed tin covers over their primary chains. Despite the introduction of the closed oil circuit on the W models this arrangement stayed unchanged while 1973 when the last servicar left the assembly belt.

As for any of the pre-war bikes good condition parts are a rare thing. It's The Cyclery that provides them.