Thanks Ian. But 66-3058 doesn’t fit with that cover. 66-3058 has 6 coils. Because of the strengthening ribs around the kickstart shaft, the total height of the spring doesn’t allow the kickstart ratchet to fully seat.
According to Neale Gentner’s excellent gearbox info (below), it sounds like 24-4300 is correct, with 65-3135 as a potential backup, but I was hoping someone with a 66-3064 cover could confirm.