The S&S circuit breaker gears for generator big twin style engines are made to the same high quality standards as all other S&S gears. They are available for engines from 1936-'69 in two versions. The standard version turns the timer in the stock clockwise rotation and is meant as a direct replacement for stock gears to be used with stock style timers. Our counterclockwise or reverse rotation version changes rotation to the opposite direction, enabling the builder to use the S&S and other aftermarket timers with the S&S Super Stock electronic ignition and some other aftermarket ignition systems. The circuit breaker drive gear is slightly narrower than stock, allowing the use of generator style cams with 1984-'99 style lobe design. Includes circuit breaker drive gear and idler gear assemblies, circuit breaker gear, and two average size shims. Fits 1936-'69 big twin engines and custom alternator/generator engines. S&S Part #: 33-4227