Harley-Davidson Duo-Glide 74 OHV & Servi-Car 1958–1959 Service Manual (P/N 99482-59)

• Target Models: Built for owners and workshops servicing the 1958–1959 Harley-Davidson Duo-Glide 74 OHV and FL/FLH variants.
• Official OEM Reference: Publication P/N 99482-59, serving as the definitive factory resource for late 1950s Big Twin builds and teardowns.
• 140 Pages of Technical Data: Includes 85+ exploded-view diagrams, transmission gear ratios, and exact valve timing specifications.
• Extensive Shop Operations: Delivers guidance on routine maintenance, diagnostic testing, electrical system troubleshooting, primary chain adjustments, and complete Linkert carburetor overhauls.
• Dedicated Component Breakdown: Features detailed service parameters for the Model 58 generator, ignition coil, voltage regulator, starter clutch, and scavenge oil pump.

Document Coverage and Technical Insight

The 1959 Harley-Davidson Duo-Glide 74 OHV service manual provides the exact mechanical specifications and assembly guidelines needed for the classic Big Twin platform. Whether you are a professional technician or a dedicated DIYer, having the right factory data on hand in this digital PDF prevents assembly delays and ensures components are mated to strict OEM standards. By cross-referencing precise factory clearances directly at the workbench, you establish a streamlined workflow that mitigates the risk of a catastrophic secondary repair. Detailed sections map out the 1,207 cc V-type Panhead engine, covering critical ranges like valve spring tension, tappet clearances, and oil pump pressure benchmarks. You will also find comprehensive breakdowns of the Hydra-Glide front forks, outlining proper oil filling methods and bushing reaming procedures.

Instead of outsourcing complex jobs to a specialty machine shop, mechanics can utilize the documented step-by-step procedures for intricate tasks like lacing and truing spoked wheels, lapping connecting rod races, and refinishing cylinders. For drivetrain work, the document dives deep into the transmission and clutch systems. It details 4-speed gear box ratios, shift linkage adjustments, and internal disc clearances. Working on vintage motorcycles requires precision and a strict awareness of mechanical safety; always secure the bike on a stable lift and double-check tension loads before starting heavy teardowns or alignments.

When executing a gearcase rebuild on these late 1950s platforms, technicians often encounter hidden pitfalls. For example, improper timing of the crankcase breather valve during a bottom-end repair will inevitably lead to severe wet-sumping and crankcase pressurization. Furthermore, failing to accurately polarize the generator before initial startup will instantly destroy a new voltage regulator, a common trap for those working without original factory procedures. To support accurate fault isolation, the file contains the essential Wiring diagrams, along with specific visual aids like the Regular Lubrication and Service Intervals chart, an Engine Cutaway view, the Oil Feed Pressure System schematic, the Frame with Basic Dimensions drawing, and a Clutch Assembly exploded view.

The text highlights crucial assembly tolerances, such as connecting rod alignments, cylinder bore measurements, and piston ring gaps. Factory reference values establish main bearing end play at 0.0001–0.0010 in. for optimized engine rotation, while transmission gear backlash is set at 0.003–0.006 in. And when you are setting up the front end, the guidelines specify exactly 7 oz. of hydraulic fork oil per slider tube for standard units.