| Parameter | Specification |
|---|---|
| Production Years | 1966–1980 |
| Engine Type | 45° V-Twin Shovelhead (1200cc / 74ci) |
| Oil Grade | SAE 50 (>60°F) / SAE 60 (>80°F) |
| Oil Capacity | 3.8 Liters |
| Tire Size (F/R) | 5.00 x 16 / 5.00 x 16 |
| Spark Plug | Champion RN12YC (0.75mm Gap) |
| Battery | Y60-N24L-A |
Engineering Highlight: The ‘Power-Pac’ Revolution
A pivotal moment in Milwaukee history occurred in 1966 when the FLH-74 introduced the ‘Shovelhead’ top end. Replacing the aging Panhead, the Shovelhead featured redesigned ‘Power-Pac’ aluminum cylinder heads. This engineering shift wasn’t merely aesthetic; the shallow combustion chamber and improved porting geometry resulted in a 10% increase in power output, allowing the heavy Electra-Glide chassis to maintain highway speeds with significantly improved thermal efficiency.
Technical Maintenance Protocol
Lubrication System
The Shovelhead is a dry-sump system that demands high-viscosity single-grade oils to maintain film strength in air-cooled tolerances. At MotoSpecsLab, we emphasize using SAE 50 for standard cruising, but transitioning to SAE 60 is mandatory if operating in ambient temperatures consistently exceeding 80°F. The 3.8-liter reservoir must be monitored for ‘sumping’—a common issue where oil migrates into the crankcase during long periods of storage.
Chassis & Contact Patch
The FLH-74 utilizes a classic 5.00 x 16 balloon tire configuration on both ends. This setup provides the signature ‘cushion’ ride but requires precise pressure management. Under-inflation leads to heavy handling and sidewall overheating. We recommend 1.4 bar (20 psi) for the front and 1.7 bar (24 psi) for the rear to balance footprint and stability.
Ignition & Electrical
Reliability in the 1200cc Shovelhead is contingent upon the secondary ignition circuit. The Champion RN12YC is the gold standard for this engine; ensuring a 0.75mm gap is critical to prevent fouling during low-speed idling. The electrical system relies on the high-capacity Y60-N24L-A battery, which provides the necessary cold cranking amps to turn over the heavy flywheels of the 74-cubic-inch mill.
MotoSpecsLab Verdict
The FLH-74 Electra-Glide remains the quintessential American tourer. While it requires a more ‘hands-on’ maintenance schedule than modern Twin-Cams or Mil-8s, its mechanical soul is unmatched. For the collector or vintage rider, adhering to the high-viscosity oil requirements and precise ignition timing is the key to longevity for this 1200cc icon.