S&S steel rotary breather gears have better dimensional stability than plastic gears, especially at high temperatures. Abrasive particles are less likely to get embedded in a steel gear body— embedded particles can damage the crankcase breather gear cavity. A screen provides better protection than a slotted gear— small particles are stopped from getting to the gear cavity where they may damage the gears and oil pump. S&S steel rotary breather gear features a welded-in screen and larger diameter holes, providing improved air flow/oil scavenging from the flywheel cavity. Crankcase flywheel cavity vacuum and oil scavenging are further improved by optimized breather window timing. Breather oil trap scavenging is significantly improved by increased scavenge port duration.
S&S steel rotary breather gears are available for all OHV engines from 1936- ‘84 in standard and +.030" oversize for repair jobs where the cases have been damaged.
Breather gear kits include breather gear and steel end play shim kit.