Design Improvements for the Zenith 601 HDS: Cowl Shape

Cowl Shape

The cowl is tightly fitted, to the extent that small bumps are needed to accommodate the tops of the carburetors and the exhaust pipe leaving the left front cylinder. Notice the pronounced lip at the bottom. It makes sure that the cooling air from the front inlet, the radiator, and the oil cooler exits the cowl promptly. Without that lip, proper cooling is not possible.