1958–1959 Harley-Davidson Duo-Glide 74 OHV FL/FLH Service Manual (P/N 99482-59)

This Harley-Davidson service manual, P/N 99482-59, covers maintenance, troubleshooting, and major repair for the 1958–1959 Duo-Glide 74 OHV, including FL and FLH variants. Servi-Car coverage is limited to shared component sections, including front forks and selected electrical systems.

PDF Access, Diagram Detail, and Page Count

Search, navigation, and wiring detail: PDF text search is not available, and there are no embedded bookmarks. Small terminal numbers and wire-color codes in the Standard and Radio-Special wiring diagram are readable when enlarged.

One printable English-language PDF contains 140 pages: 129 service pages and 11 included cover, preliminary, and divider pages. These comprise the front and back covers, title page, foreword, contents page, and six section dividers.

Engine Overhaul, Chassis Service, and Electrical Diagnosis

The following selected highlights outline the main workshop coverage. Additional topics include seat-post spring service and speedometer drive-core maintenance.

• Maintenance and troubleshooting: The Regular Lubrication and Service Intervals chart accompanies fault lists for hard starting, overheating, charging problems, clutch faults, and poor braking.

• Engine repair: Cylinder-head removal, valve and guide service, cylinder refinishing, piston inspection, crankcase disassembly, and bearing fitting.

• Fuel system: Carburetor disassembly and reassembly, float and needle checks, throttle-shaft bushing replacement, air-cleaner service, and fuel-strainer cleaning.

• Drive and transmission: Primary and rear chain adjustment, clutch repair, kickstarter and starter-clutch service, shifting-linkage adjustment, and gearbox overhaul.

• Chassis and brakes: Wheel-hub service, wheel lacing and truing, Hydra-Glide fork repair, rear suspension inspection, brake-cylinder service, and hydraulic brake bleeding.

• Charging and ignition: Model 58 and 58R generator tests, voltage-regulator diagnosis, ignition timing, coil troubleshooting, and wiring diagrams with connection keys.

The manual introduces readers to basic maintenance and repair while presenting major repair methods for professional Harley-Davidson mechanics; its machining and bearing-fitting work calls for suitable measuring equipment and workshop tools.

Engine Fits, Lubrication, and Rebuilding

Factory clearances and assembly illustrations let you compare worn parts with documented fits before deciding what needs replacement. The Engine Cutaway and Oil Feed Pressure System drawings explain the relationship between the hydraulic lifters, rocker arms, and oil passages.

The engine sections cover valve-spring testing, hydraulic tappet checks, cylinder-bore measurement, piston-ring fitting, and connecting-rod alignment. Step-by-step procedures extend to lapping connecting-rod races and truing flywheels, with dedicated tooling identified for these operations.

Oil feed and scavenge pump inspection accompanies valve and crankcase-breather timing information. The piston section warns that an incorrectly installed piston-pin lock ring can come loose and damage both the piston and cylinder.

Carburetor Checks and Drivetrain Service

Carburetor coverage distinguishes mixture adjustment from mechanical faults involving the float valve, throttle shaft, and venturi. It also directs attention to ignition condition, air-cleaner restriction, and manifold connections before carburetor adjustment.

The transmission section separates checks that can be made with the unit installed from work requiring removal. The Clutch Assembly exploded view supports disc and spring inspection, while shifter-fork adjustment identifies Fork Shifter Gauge 96384-39. Three-speed-and-reverse differences are called out within the gearbox procedures.

Fork Variants, Wheels, and Hydraulic Brakes

Front-fork coverage distinguishes the non-adjustable solo fork from the adjustable fork used for solo or sidecar operation. Slider-bushing replacement includes reaming procedures and identifies Bushing Reamer and Pilots 96300-50.

The Frame with Basic Dimensions drawing supports preliminary alignment checks. Wheel work includes step-by-step lacing and truing procedures; brake coverage extends to the rear master cylinder, wheel cylinders, and sidecar brake system.

Rear shock coverage includes spring adjustment, assembly removal, and inspection. Faulty hydraulic shock absorber units require replacement; the manual does not provide internal repair procedures for those units.

Secure the motorcycle on a stable stand before wheel, fork, or drivetrain work.

Generator Tests and Ignition Fault Isolation

Charging-system checks help distinguish generator faults from regulator or wiring problems before component teardown. Separate procedures address the standard Model 58 generator and the Model 58R radio generator, including field-coil and armature testing.

Ignition coverage includes breaker-point inspection, timing-mark and test-lamp checks, and spark-plug cable replacement. The generator section warns that incorrect polarity can burn relay contacts and damage the generator.

Selected Bearing, Gear, and Fork-Fill Specifications

Bearing and gear clearances: The engine specification table lists sprocket-shaft bearing end play at 0.0001–0.010 in. Transmission specifications give gear backlash as 0.003–0.006 in.

Fork filling: The Hydra-Glide fork section specifies 6-1/2 oz. per tube for an oil change and 7 oz. per tube after disassembly and washing. The quantities apply to different filling conditions.