1941–1946 BMW R75 Service Manual (P/N 01 99 9 099 421)

• Reproduces an English-language BMW factory workshop manual in a 187-page scanned PDF, with coverage identified throughout for the R 60/6, R 75/6, R 90/6, and R 90 S.
• Documents compression testing, engine removal, cylinder and cylinder-head repair, valve-guide and seat work, crankshaft and main-bearing service, pistons, timing drive, seals, valve adjustment, and oil-pump repair.
• Follows the dry clutch, five-speed gearbox, selector mechanism, kickstarter, enclosed drive shaft, and final drive through removal, inspection, repair, setup, and refitting.
• Separates the model-specific Bing slide, Bing constant-depression, and Dell’Orto accelerator-pump carburetors, including idle adjustment, synchronization, fuel-level checking, cleaning, choke service, and air-filter maintenance.
• Distinguishes the R 60/6 duplex front drum, R 75/6 and R 90/6 single-disc front brakes, and R 90 S twin-disc arrangement, then covers hydraulics, suspension, steering, wheels, spokes, balancing, and bearings.
• Provides ignition, alternator, regulator, diode-carrier, and starter diagnostics; factory fault charts; a keyed wiring diagram; special-tool references; torque data; capacities; clearances; wear limits; and model-specific test specifications.

This manual reproduces workshop information published by Bayerische Motoren Werke AG, Customer Service Department. BMW’s foreword states that it was prepared for master mechanics and fitters whose practical and theoretical service training would be supplemented by the book. Its assumed familiarity with precision measurement, presses, heating equipment, and dedicated fixtures makes it best suited to trained technicians and highly experienced restorers, rather than beginners looking for routine owner maintenance.

Model-Specific Service Information

The carburetor coverage is divided by installed equipment instead of treating every /6 model alike. The R 60/6 uses Bing 1/26/111 and 1/26/112 slide carburetors; the R 75/6 uses Bing 64/32/9 and 64/32/10 constant-depression units; and the R 90/6 uses Bing 64/32/11 and 64/32/12 units. The R 90 S section addresses Dell’Orto PHM 38 BS and PHM 38 BD carburetors with accelerator pumps. Relevant repair pages show model-appropriate adjustment, fuel-level, cleaning, choke, and removal details.

The same distinction continues through the chassis and electrical chapters. Brake procedures match each front-brake configuration, while the complete wiring diagram identifies the R 90 S-only voltmeter and the optional clock. Steering data also recognizes the U.S.-market handlebar variation.

Full-Motorcycle Repair Coverage

Beyond the engine, the manual covers clutch work, gearbox disassembly and shimming, selector and kickstarter service, drive-shaft removal, and crown-wheel and pinion setup in the rear drive. Chassis chapters address telescopic-fork overhaul, steering adjustment, swingarm bearings, spring struts, hydraulic brake bleeding, caliper and master-cylinder repair, wheel bearings, spoke replacement, and static balancing. Fuel-tank, exhaust, frame, stand, seat, instrument, lighting, battery, relay, and horn work is also included.

Technical Data pages introduce the major repair groups with dimensions, fits, capacities, wear limits, repair sizes, torque values, and test criteria. Supporting visuals include the cylinder-head tightening-sequence drawing, compression-indicator graph, alternator and diode-carrier test layouts, alternator and starter fault-finding charts, and the full vehicle wiring diagram with cable-color and component keys.

Tools, Cautions, and Scope

Factory fixtures shown in use include the BMW No. 6000 assembly stand with No. 6005/1 engine/gearbox jig, No. 269 cylinder-head thrust bridge, No. 213 timing-sprocket extractor, No. 534 clutch clamping bolts, and No. 529/1 clutch-centering arbor. The manual also flags repair traps, including timing-chain links damaging sprocket rivet studs during removal and projecting spoke ends threatening an inner tube after wheel repair.

For safe workshop use, disconnect the battery ground before electrical repair, keep fuel-system work ventilated and away from ignition sources, and protect painted surfaces from brake fluid. The foreword identifies Order No. 01 99 9 099 421 as a separate Special Tool Catalogue—not as this workshop manual’s publication number. That catalogue and the separate Spare Parts Catalogue are not included; this PDF shows relevant tools in context but is not a complete tool or parts-number reference.