1986–1991 BMW K 75, K 75 C, K 75 S, K 75 RT Service Manual

This 96-page Spanish-language PDF, Revista Moto Técnica No. 14, covers the 1986–1991 BMW K 75 lineup, including the C, S, and RT variants and ABS-equipped models. Written for professional technicians and experienced home mechanics, it combines routine maintenance with repair work that often requires special tools and measuring equipment.

• Engine removal, cylinder-head repair, camshaft inspection, and timing-chain replacement, supported by timing-mark diagrams.
• Bosch LE-Jetronic fuel-pressure testing, throttle-body synchronization, throttle-switch adjustment, and exhaust-CO checks.
• Dry single-disc clutch inspection and release adjustment, plus five-speed transmission disassembly and shaft shimming.
• Driveshaft inspection and rear bevel-drive overhaul, including bearing preload, gear backlash, and contact-pattern checks.
• Standard and Sport front-fork rebuilding, steering-bearing service, and drum, disc, and ABS brake procedures.
• Electrical fault tracing for the Bosch ignition system, alternator, and starter, with test tables and wiring diagrams.

Engine repair and fuel-injection diagnosis

The engine chapters cover the longitudinal, liquid-cooled 740 cc three-cylinder unit. Internal repair includes crankshaft and connecting-rod inspection, piston and ring assessment, and intermediate-shaft installation and timing. The text distinguishes jobs performed with the engine in the frame from work requiring removal. Component-specific torque specifications accompany camshaft clearance data, cylinder-head fastening specifications, wear limits, and bearing-shell selection information.

Valve-clearance service includes shim selection and identifies BMW tappet tool 11.1.721. Lubrication and cooling coverage extends to the combined oil/water pump, seal replacement, thermostat and fan testing, and circuit pressure checks. Fluid-capacity data and a labeled cooling-circuit diagram support these sections. The engine assembly notes warn that a trapped intermediate-shaft bearing locating ring can damage the crankcases.

In the injection section, a terminal-by-terminal troubleshooting table connects test conditions and electrical readings with faults in the airflow meter, temperature sensor, injectors, and supply circuits. The LE-Jetronic system schematic shows how the components connect. Separate symptom tables address starting problems, rough running, loss of power, and overheating.

Fuel-system work calls for ventilation and control of ignition sources; the manual warns that an energized pump can spray gasoline from disconnected lines.

Clutch, gearbox, and final drive

Clutch repair covers the friction disc, diaphragm spring, pressure plates, and release mechanism. Dimensioned drawings identify the BMW 21.2.670 centering tool and 11.2.800 holding plate. Related sections cover the rear engine seal, alternator drive, and starter freewheel.

A gearbox shaft end-float measurement diagram supports shim selection, while final-drive data distinguish standard and optional reduction ratios and housings for drum- versus disc-brake models. The gearbox chapter warns that removing transmission shafts in the wrong sequence can damage the input-shaft bearing. Production-change notes also distinguish early and later intermediate-shaft drive gears and crankshaft thrust-bearing arrangements.

Chassis variants and ABS limits

Variant notes separate the standard fork and rear drum brake of the K 75 C and 1987–1989 K 75 from the Sport fork and rear disc of the K 75 S, RT, and 1990–1991 K 75. Chassis repair extends to the Monolever swingarm bearings, front-wheel bearings, brake calipers, and master cylinders.

ABS coverage includes wheel-sensor gap checks, warning-lamp behavior, and a dedicated electrical connection schematic. Pressure-modulator service is limited to bleeding; electronic faults beyond preliminary checks are referred to BMW dealers with the dedicated diagnostic tester.

The general K 75 wiring diagram includes component legends and wire-color keys. Electrical specifications cover alternator output, while the repair sections explain brush inspection, winding tests, and rectifier-diode checks. Ignition testing includes timing and Hall-sensor circuits, with a distinction between checks using ordinary electrical meters and those requiring BMW test equipment.