1985–1991 Honda CR500R Factory Service & Repair Manual (P/N 61KA509)

• Document identity and coverage: Official Honda factory shop manual for the 1985-1991 CR500R, Honda Item/Part No. 61KA509, in a 259-page PDF. Includes model-identification data, frame and engine serial references, and later-production callouts marked "After '88."
• Engine and drivetrain repair: Covers engine removal and installation, cylinder-head and top-end service, clutch and gearshift work, kickstarter repair, crankcase separation, five-speed transmission service, crankshaft inspection, and crankcase-bearing replacement.
• Fuel-system and race setup: Explains the year-specific PJ carburetors, starting/idle, slow, and main circuits; minor and major adjustment; altitude and temperature correction; optional jetting parts; float and jet service; and reed-valve inspection.
• Front chassis repair: Details front-wheel service, fork disassembly and reassembly, bushing and seal replacement, damping-component inspection, steering-stem repair, and procedures specific to the 1985-1988 and later fork arrangements.
• Rear chassis and brake work: Includes rear-wheel service, the 1985-1986 drum brake, later hydraulic rear disc brake, swingarm and linkage inspection, gas-charged shock overhaul, brake-fluid replacement, air bleeding, and master-cylinder and caliper repair.
• Ignition and fault finding: Provides alternator, CDI, ignition-coil, timing, and engine-stop-switch tests; 1985, 1986, and after-1986 wiring diagrams; plus diagnostic charts for starting trouble, power loss, high- and low-speed running faults, and poor handling.

Factory Repair and Diagnostic Coverage

This manual is built around Honda's liquid-cooled, 491.4 cc single-cylinder two-stroke and its constant-mesh five-speed transmission. Its depth and special-tool requirements make it best suited to experienced owners and technicians who are already comfortable with full engine teardown, precision inspection, hydraulic-brake service, and suspension work.

The opening chapters pair Honda's competition maintenance schedule with lubrication points, cable and harness routing, the optional-parts list, and year-specific model identification.

The engine chapters go well beyond routine maintenance. Top-end repair can be performed with the engine in the frame, while crankshaft and transmission work is documented through complete crankcase separation and reassembly. The specifications distinguish a 650 cc routine transmission-oil change from the 700 cc refill after disassembly. They also separate the 1985-1986 cylinder-to-piston clearance of 0.050-0.085 mm from the after-1986 range of 0.070-0.105 mm. Component-specific torque tables, inspection limits, runout checks, gear and bearing measurements, and cooling-system test data support the repair procedures.

Carburetor coverage is unusually practical for a competition manual. Honda explains which metering circuit controls each throttle range, then supplies an air-density correction graph and a jet-needle/air-screw chart for altitude and temperature changes. Standard carburetor identification progresses from PJ21A through PJ27C by model year, with separate jet, needle, clip-position, and air-screw data. The section also covers carburetor removal, disassembly, float-level setting, installation, reed-valve inspection, fuel-tank service, and air cleaner case removal.

Model-Year Changes That Matter

The seven model years are not treated as mechanically identical. The identification section lists full frame and engine number ranges for 1985-1987, beginning numbers for 1988 and 1989, and serial-number locations. Procedure and specification callouts then separate the 1985-1986 rear drum setup from the hydraulic rear disc used after 1986, earlier and later fork and steering assemblies, revised shock components, post-1987 transmission details, and the "After '88" engine, chassis, brake, and carburetor changes that apply through 1991.

Front-fork coverage includes the distinct teardown and assembly paths used across the production run. The rear-suspension chapter extends from wheel and linkage service into shock reservoir, bladder, damper, seal, oil-filling, air-bleeding, and nitrogen-charging work. Detailed spring-preload adjustment is referred to the separate Owner's Manual, an important scope limit for race-sag setup.

Drawings, Tools, and Shop Cautions

The visual material includes cable and harness routing views; carburetor starting/idle, slow, and main-circuit schematics; crankcase and transmission exploded views; fork and shock component views; hydraulic master-cylinder and caliper layouts; and year-specific ignition wiring diagrams. Troubleshooting charts connect symptoms to checks for fuel delivery, spark, compression, clutch drag or slip, overheating, jetting, wheel and steering faults, and suspension behavior.

Honda tool numbers are given where the repair depends on dedicated equipment, including crankcase puller 07937-4300000, water-seal driver 07945-KA30000, 1985-1988 fork-seal tools 07947-KA40200 and 07947-KA50100, and steering-stem socket 07916-KA50100. Two cautions are especially easy to miss: the carburetor jet block is not intended to be removed from the body, and ordinary hardware must not replace the correctly oriented Honda rear-linkage and shock mounting bolts because it lacks the required strength.

Fuel-system work, hydraulic-brake service, and gas-charged shock disassembly carry specific hazards. Follow the manual's ventilation, brake-dust, pressure-release, and nitrogen-only precautions, and support the motorcycle securely before chassis repair.