Harley-Davidson Servi-Car & 45 SV 1940–1958 Service Manual

This 1986 Antique Cycle Supply Inc. service manual covers Harley-Davidson Servi-Car and 45 SV models under its 1940–1958 title. It combines military WLA service procedures with Servi-Car specifications, maintenance references, and chassis repair sections.

PDF Access and Diagram Detail

Search, navigation, and wiring labels: PDF text search is not available, and there are no embedded bookmarks. Small wire-color labels and terminal numbers in the WLA wiring diagrams require zooming.

One printable English PDF contains 82 pages, including 11 pages of Servi-Car reference and repair material, a one-page index, and one page each for the front and back covers.

Flathead Engine, Drivetrain, and Chassis Work

The following selected coverage highlights outline the main workshop areas. Other included topics range from handlebar-control servicing to saddle spring-post adjustment.

• Engine overhaul: Step-by-step instructions for top-end and complete overhaul, cylinder reboring and rehoning, valve-guide service, piston fitting, and flywheel truing.

• Lubrication system: Oil-feed and scavenger-pump installation, crankcase-breather timing, engine lubrication schedules, and chain-oiler adjustment.

• Fuel system: Linkert Model M carburetor disassembly, passage cleaning, float-and-needle inspection, and mixture adjustments.

• Transmission and clutch: Transmission removal, bearing inspection, mainshaft endplay adjustment, shifter setup, clutch disassembly, and clutch-hub service.

• Electrical diagnosis: Generator fault isolation, field-coil and armature tests, circuit-breaker service, ignition timing, and WLA wiring diagrams.

• Wheels and steering: Wheel-hub adjustment, rim centering, fork and frame alignment checks, steering-damper assembly, and mechanical-brake adjustment.

• Servi-Car chassis: Differential and axle overhaul, box removal and installation, chain adjustment, hydraulic-brake linkage adjustment, and brake bleeding.

The overhaul material suits mechanics and experienced restorers familiar with precision fitting; bearing work and alignment checks call for measuring equipment and specialized workshop tools.

Engine Fitting and Oil-System Details

The engine section distinguishes upper-end work with the crankcase remaining in the frame from complete removal and lower-end overhaul. Valve-seat refacing, tappet-guide service, connecting-rod alignment, and oversize piston selection extend the coverage beyond routine maintenance.

Bearing-race lapping and flywheel truing are separate operations. The manual identifies lapping arbor 11954-40 for the main-bearing races and truing device 11962-X for flywheel-shaft alignment.

The Lubrication Chart and Engine Oiling System schematic connect maintenance points with the feed, return, and breather arrangements. The oil-feed-pump gasket warning explains how a misplaced passage can interrupt lubrication and expose the engine to serious damage. Breather timing is covered separately because it controls crankcase scavenging.

Linkert Carburetor Variations

The fuel-system chapter distinguishes external and internal vent arrangements across the military Model M carburetors. Sectional views show the nozzle, float mechanism, idle passages, and fixed-jet arrangement.

Most listed military versions use fixed high-speed jets, while the M-641 uses an adjustable high-speed needle. The specifications table links carburetor models to their venturi, idle-hole, and jet details, helping match the service information to the fitted carburetor.

Transmission Assembly and Electrical Fault Finding

Transmission and clutch exploded views support checking part orientation during reassembly. The parts tables and fitting instructions distinguish the 1940 arrangement from the later design, including the tapered versus splined clutch-hub mounting.

The generator test sequence helps separate generator faults from cut-out-relay or charging-circuit wiring problems. Further procedures cover brush inspection, armature testing, commutator work, and ignition-light-switch repair. Relay adjustment calls for a qualified electrical specialist and closely calibrated instruments.

WLA wiring diagrams distinguish harness configurations by U.S.A. registration number. A separate diagram identifies the added radio-interference suppression components.

Servi-Car Axle, Frame, and Brakes

The Servi-Car material includes the Basic Frame Dimensions drawing and Differential and Axle exploded view. Rear-end procedures address housing disassembly, bearing inspection, axle endplay, and differential reassembly.

Later Servi-Car coverage is limited to the included reference, maintenance, chassis, chain, axle, and brake sections. The axle-housing instructions warn that overtightened truss rods can bow the housing and axle, accelerating wear.

For two-wheel chassis work, the fork checks are described as emergency checks; normal straightening and accurate alignment require suitable shop equipment. Brake and structural repairs require the appropriate training or assistance from a qualified mechanic.

A Preview of Piston Fit and Transmission Endplay

The engine fitting summary specifies piston-to-cylinder clearance of 0.001–0.002 inch, measured front to rear at the bottom of the skirt. This applies to the manufacturer’s taper-cam-ground piston; the manual expressly warns that it is insufficient for straight-cam-ground replacement pistons.

For the transmission assembly described, mainshaft endplay is 0.003–0.005 inch with the side cover and gasket secured as in final assembly. Low- and second-gear endplay between the retaining bracket and side cover is specified separately at 0.005–0.007 inch.