1988 Suzuki RM 250 Repair Manual

The 1988 Suzuki RM 250 is a high-performance motocross motorcycle featuring a liquid-cooled 2-stroke 249cc engine, 5-speed transmission, front and rear suspension systems, and advanced chassis design. This repair manual covers complete maintenance, troubleshooting, and repair procedures for all major components including engine, transmission, suspension, brakes, electrical system, and chassis. Below are key sections for specifications, maintenance schedules, engine repair, transmission service, suspension adjustment, electrical troubleshooting, and common issues.

1. Specifications 2. Maintenance Schedule 3. Engine Repair 4. Transmission Service 5. Suspension Systems 6. Brake Systems 7. Electrical System 8. Carburetor Service 9. Chassis & Frame 10. Troubleshooting Guide

Specifications

Complete technical specifications for the 1988 Suzuki RM 250 motocross motorcycle.

Component	Specification
Engine Type	Liquid-cooled 2-stroke single cylinder
Displacement	249cc
Bore x Stroke	67.0 x 70.8mm
Compression Ratio	8.5:1
Carburetor	Mikuni VM36SS
Ignition System	CDI electronic ignition
Transmission	5-speed constant mesh
Final Drive	520 chain
Front Suspension	Kayaba conventional forks, 11.8" travel
Rear Suspension	Full-floating Kayaba shock, 12.2" travel

Maintenance Schedule

Recommended maintenance intervals for optimal performance and longevity.

After every ride: Clean air filter, check tire pressure, inspect chain tension.
Every 10 hours: Change transmission oil, check spark plug, inspect brakes.
Every 20 hours: Clean carburetor, check suspension settings, inspect wheel bearings.
Every 50 hours: Top-end rebuild, check reed valves, inspect clutch plates.
Seasonal: Full suspension service, bearing replacement, frame inspection.

WARNING! Always use proper safety equipment and follow torque specifications. Engine components operate under high stress.

Engine Repair

Complete engine disassembly, inspection, and reassembly procedures.

Cylinder head removal: Drain coolant, remove head bolts in criss-cross pattern.
Cylinder removal: Remove exhaust pipe, intake manifold, and cylinder base nuts.
Piston replacement: Remove circlips, wrist pin, install new rings with gaps staggered.
Crankcase splitting: Remove all engine covers, separate cases using case splitter tool.
Reed valve inspection: Check for cracks or warping, replace if necessary.

CAUTION! Use proper gasket sealant and torque all fasteners to specification. Clean all mating surfaces thoroughly.

Transmission Service

Oil Change: Drain plug torque 18 ft-lbs, capacity 750ml.
Clutch Service: Fiber plate thickness 2.9-3.1mm, steel plates must be flat.
Shift Mechanism: Check shift forks for wear, replace if bent.
Gear Inspection: Check for worn dogs and engagement surfaces.
Bearing Replacement: Press bearings using proper tools only.
Seal Installation: Lubricate seals before installation.
Shift Drum: Inspect for wear on cam surfaces.
Kickstarter Mechanism: Check ratchet engagement and spring tension.

Suspension Systems

Front and rear suspension maintenance, adjustment, and rebuild procedures.

Front Forks: Oil capacity 435ml per leg, oil level 130mm from top. Spring rate 0.40 kg/mm. Compression damping 12 clicks out from full stiff.

Rear Shock: Nitrogen pressure 142 psi, sag setting 95-105mm. Rebound damping 10 clicks out. High-speed compression adjustment 1.5 turns out.

Swingarm: Check pivot bearings for play, grease every 20 hours. Chain adjustment 1.5-2.0 inches free play.

Brake Systems

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

Front brake pads: Remove caliper bolts, replace pads when worn to 1mm.
Rear brake shoes: Remove wheel, check for even wear and contamination.
Brake bleeding: Use DOT 4 fluid, pump lever until firm, check for leaks.
Cable adjustment: Maintain 10-15mm free play at lever.

Tip: Always clean brake components with brake cleaner only. Never use compressed air on brake systems.

Electrical System

Complete electrical system troubleshooting and component testing.

CDI testing: Check resistance values against specification chart.
Stator output: AC voltage should be 50V+ at kickstart speed.
Spark plug: NGK BR9ES, gap 0.6-0.7mm.
Kill switch: Continuity test when pressed, open circuit when released.
Lighting coil: Output 12V AC for headlight and taillight.
Wiring harness: Check for chafing, proper grounding points.
Voltage regulator: Test diode function with multimeter.
Ignition coil: Primary resistance 0.1-0.3Ω, secondary 4.7-7.2kΩ.

WARNING! Disconnect battery before electrical work. High voltage from ignition system can cause severe shock.

Carburetor Service

Mikuni VM36SS carburetor jetting, cleaning, and adjustment procedures.

Chassis & Frame

Frame inspection, bearing replacement, and chassis maintenance.

Steering head bearings: Adjust for zero play, grease annually. Wheel bearings: Check for smooth rotation, replace if rough. Frame cracks: Inspect at stress points after hard impacts. Subframe alignment: Check for straightness after crashes.

CAUTION! Always support motorcycle properly when working on chassis components. Use torque wrench for all critical fasteners.

Troubleshooting Guide

Symptom	Possible Cause	Corrective Action
Hard starting	Fouled plug, weak spark	Replace spark plug, check CDI output, clean carburetor.
Poor performance	Clogged jets, air leak	Clean carburetor, check reed valves, pressure test engine.
Transmission noise	Worn bearings, bent shift fork	Inspect transmission components, replace damaged parts.
Oil leakage	Worn seals, loose fasteners	Replace crank seals, check case mating surfaces.
Overheating	Low coolant, water pump failure	Check coolant level, inspect water pump impeller.

Technical Support: Contact Suzuki customer service for factory technical assistance.

Parts Availability: Genuine Suzuki parts available through authorized dealers.