1988 Honda CR250 Service Manual

The 1988 Honda CR250 is a high-performance 250cc two-stroke motocross motorcycle featuring liquid cooling, Pro-Link rear suspension, and a powerful engine designed for competitive racing. This service manual covers complete maintenance procedures, specifications, troubleshooting, and repair instructions for all major systems including engine, transmission, suspension, brakes, and electrical components.

1. General Information 2. Specifications 3. Periodic Maintenance 4. Engine 5. Carburetor 6. Transmission 7. Suspension 8. Brakes 9. Electrical System 10. Troubleshooting 11. Wiring Diagrams

General Information

This manual provides detailed service information for the 1988 Honda CR250R motocross motorcycle. Includes identification numbers, safety precautions, and general maintenance procedures.

Component	Description
Model	CR250R
Engine Type	249cc liquid-cooled two-stroke single
Frame Type	Semi-double cradle steel frame
Suspension Front	43mm Showa conventional fork
Suspension Rear	Pro-Link single shock
Brakes Front	Single disc
Brakes Rear	Single disc
Fuel Capacity	2.3 gallons
Dry Weight	216 lbs

Specifications

Engine: 249cc liquid-cooled two-stroke single cylinder
Bore x Stroke: 67.0 x 70.8mm
Compression Ratio: 8.4:1
Carburetor: 38mm Keihin PWK
Ignition: CDI electronic ignition
Transmission: 5-speed constant mesh
Final Drive: #520 chain
Front Suspension: 43mm Showa telescopic fork, 11.8" travel
Rear Suspension: Pro-Link single shock, 12.6" travel
Front Tire: 80/100-21
Rear Tire: 110/90-19

Periodic Maintenance

Regular maintenance schedule and procedures to ensure optimal performance and longevity.

Pre-ride inspection: Check tires, controls, cables, fluid levels
Engine oil change: Every 15 hours or 6 races
Air filter cleaning: Every ride in dusty conditions
Spark plug replacement: Every 20 hours
Coolant change: Every 30 hours or annually
Brake fluid change: Every 60 hours or annually
Wheel bearing inspection: Every 40 hours
Suspension service: Every 60 hours or as needed

WARNING! Always use genuine Honda parts and recommended fluids for optimal performance and warranty compliance.

Engine

Complete engine service procedures including disassembly, inspection, and reassembly.

Component	Specification
Cylinder Bore	67.000-67.015mm
Piston Clearance	0.045-0.055mm
Ring End Gap	0.40-0.60mm
Crankshaft Runout	0.03mm maximum
Ignition Timing	1.8mm BTDC at 4000 RPM
Spark Plug	NGK BR9ES
Spark Plug Gap	0.6-0.7mm

CAUTION! Engine disassembly requires special tools and mechanical experience. Follow torque specifications precisely.

Carburetor

Keihin PWK carburetor service, jetting specifications, and adjustment procedures.

Main jet: #175 standard
Pilot jet: #55 standard
Needle: 6BEY30-74, clip position 3
Air screw: 1.5 turns out
Float height: 16mm
Throttle slide: #7

Tip: Adjust jetting for altitude and temperature changes. Leaner settings for high altitude/cold weather.

Transmission

5-speed transmission service, clutch adjustment, and gear inspection procedures.

Transmission Oil: Pro Honda HP Transmission Oil 80W/85W
Oil Capacity: 750ml
Clutch Type: Wet multi-plate
Clutch Cable Freeplay: 10-20mm at lever
Gear Ratios: 1st: 2.083, 2nd: 1.666, 3rd: 1.400, 4th: 1.210, 5th: 1.083

Suspension

Front fork and rear shock service, adjustment procedures, and spring rates.

Component	Specification
Front Fork Oil	Pro Honda Suspension Fluid SS-7
Front Fork Oil Capacity	435ml per leg
Front Spring Rate	0.40 kg/mm
Rear Shock Oil	Pro Honda Suspension Fluid SS-8
Rear Spring Rate	5.4 kg/mm
Fork Compression	12 clicks out standard
Fork Rebound	10 clicks out standard

Brakes

Front and rear disc brake service, pad replacement, and bleeding procedures.

Brake fluid: DOT 4
Front disc thickness: 3.5mm minimum
Rear disc thickness: 4.0mm minimum
Pad thickness: 1.5mm minimum
Bleed procedure: Pump lever, open bleeder, close bleeder, repeat until firm

WARNING! Always use fresh brake fluid and avoid contamination. Worn brakes can cause serious injury.

Electrical System

CDI ignition, lighting coil, and complete electrical system testing procedures.

Battery: Not applicable (magneto only)
Ignition Coil Resistance: Primary: 0.1-0.3Ω, Secondary: 4.7-7.2kΩ
Source Coil Resistance: 0.1-1.0Ω
Pulse Generator Resistance: 15-25Ω
Spark Output: 8mm minimum

Troubleshooting

Symptom	Possible Cause	Corrective Action
Hard starting	Fouled plug, improper jetting	Replace spark plug; check carburetor settings
Poor performance	Clogged air filter, worn piston	Clean air filter; inspect top end
Transmission noise	Worn gears, low oil	Check oil level; inspect transmission
Clutch slipping	Worn plates, improper adjustment	Adjust cable; replace clutch plates
Overheating	Low coolant, water pump failure	Check coolant level; inspect water pump

Wiring Diagrams

Complete electrical schematics for ignition system, kill switch, and all electrical components. Color-coded wiring with connector locations and ground points.

Service Support: For technical assistance contact Honda Customer Service at 1-866-784-1870 or visit www.ahm-ownerlink.com