1940–1958 Harley-Davidson Servi-Car & 45 SV Factory Service Manual (P/N 12731-29)

• Covers 1940–1958 Harley-Davidson Servi-Car and 45 SV motorcycles, documenting factory engine, drivetrain, chassis, and electrical specifications for the V-type side valve configuration
• Third-party publication, 1986 Antique Cycle Supply Inc., P/N 12731-29
• Features over 60 technical diagrams, including exploded-view assemblies for the engine, transmission, and differential housing
• Delivers 82 pages of factory-recommended tolerances and maintenance intervals often missing from general enthusiast guides
• Details crucial flathead 45 procedures, including Linkert carburetor rebuilding, flywheel truing, cylinder reboring, and WLA model diagnostics
• Outlines the servicing of the scavenger oil pump, ignition circuit breaker, cut-out relay, steering damper, transmission mainshaft, and clutch hub

Component and System Documentation

Restoring a vintage V-twin requires precise factory data. This PDF manual breaks down the complete teardown and assembly process for the 45-degree V-type engine. You will find specific details on valve guides, tappets, and proper piston fitting. Step-by-step repair instructions guide mechanics through complex procedures that usually demand an expensive trip to a specialized machine shop, such as reboring and rehoning cylinders, truing flywheels with a lapping arbor, and completely overhauling Linkert M-Series carburetors. It also maps out exact lubrication schedules for the engine oil, transmission, and chain oilers.

Beyond the motor, the guide includes comprehensive exploded-view diagrams to assist with part orientation. These cover the three-speed constant mesh transmission and the unique Servi-Car differential assembly. Additional visual aids—specifically the Lubrication Chart, the Engine Oiling System schematic diagram, WLA wiring diagrams, Linkert Carburetor sectional views, and the Basic Frame Dimensions drawing—provide essential references for accurate workshop execution. Electrical troubleshooting gets easier with included wiring schematics and generator testing procedures. On the chassis side, expect clear outlines for fork alignment, steering damper assembly, and hydraulic brake system maintenance.

For the daily workshop routine, having these era-correct specifications right at the bench eliminates the need to cross-check multiple generic forums, significantly speeding up complex rebuilds.

When working on these specific models, technicians must watch out for known repair pitfalls documented in the text. For example, using a homemade gasket on the oil feed pump is a fatal error; misaligning a single transfer hole will completely starve the engine of lubrication. Furthermore, failing to accurately index the rotary crankcase breather valve gear disrupts the scavenging cycle, leading to severe lower-end wet-sumping.

Specification Highlights

Getting the tolerances right is critical on these historic machines. The data tables provide essential clearance and torque values straight from the era. For instance, mainshaft endplay is documented exactly between 0.003 and 0.005 inches. Standard V-type piston-cylinder clearance is specified at a tight 0.001 to 0.002 inches. Fuel capacity for the trike setup is listed at 3.4 U.S. gallons.

While this 82-page reproduction is an excellent reference standard, working on vintage motorcycles carries inherent risks. Always ensure you have the proper training or consult a certified mechanic before applying these specifications to live shop work.