1988 KTM 250 Manual

The 1988 KTM 250 is a high-performance two-stroke enduro motorcycle featuring a 249cc liquid-cooled engine, 6-speed transmission, WP suspension components, hydraulic disc brakes, and advanced off-road capabilities. This manual covers maintenance procedures, specifications, troubleshooting, and operational guidelines for optimal performance and longevity.

1. Technical Specifications 2. Engine Maintenance 3. Chassis & Suspension 4. Electrical System 5. Fuel System 6. Transmission & Clutch 7. Braking System 8. Regular Maintenance Schedule 9. Troubleshooting Guide 10. Safety Precautions 11. Warranty Information

Technical Specifications

Complete technical data for the 1988 KTM 250 enduro motorcycle.

ComponentSpecification
Engine TypeSingle cylinder, 2-stroke, liquid cooled
Displacement249 cc
Bore x Stroke67 x 70 mm
Compression Ratio12.5:1
Transmission6-speed constant mesh
Final DriveChain 5/8 x 3/8"
Front SuspensionWP USD forks, 300mm travel
Rear SuspensionWP monoshock, 330mm travel
Front BrakeSingle disc, 260mm
Rear BrakeSingle disc, 220mm
Fuel Capacity9.5 liters
Dry Weight105 kg

Engine Maintenance

Proper engine care procedures for optimal performance and longevity.

  1. Spark Plug: Replace every 30 hours; use NGK BR8ES
  2. Piston & Rings: Inspect every 80 hours; replace if worn
  3. Cylinder: Check for scoring every 100 hours
  4. Cooling System: Flush coolant annually; check hoses for cracks
  5. Exhaust System: Clean expansion chamber regularly

WARNING! Always allow engine to cool before performing maintenance. Use proper safety equipment.

Chassis & Suspension

Frame maintenance and suspension setup procedures.

  1. Frame Inspection: Check for cracks at stress points monthly
  2. Front Forks: Change oil every 60 hours; 5W fork oil recommended
  3. Rear Shock: Rebuild every 100 hours or as needed
  4. Steering Head: Adjust bearings every 40 hours
  5. Swingarm: Lubricate bearings every 50 hours

CAUTION! Use proper torque specifications when tightening chassis components.

Electrical System

Fuel System

Carburetor settings and fuel mixture specifications.

Carburetor: Mikuni VM36SS, main jet 380, pilot jet 40, needle clip position 3

Fuel/Oil Mixture: 40:1 with high-quality 2-stroke oil

Fuel Filter: Clean every 20 hours; replace annually

Throttle Cable: Lubricate monthly; check for smooth operation

Transmission & Clutch

Gearbox maintenance and clutch adjustment procedures.

  1. Transmission Oil: Change every 30 hours; use 10W-40 motorcycle oil
  2. Oil Capacity: 750ml for complete change
  3. Clutch Adjustment: Free play 2-3mm at lever
  4. Clutch Plates: Replace if slipping or dragging occurs
  5. Shift Mechanism: Check for proper engagement monthly

Tip: Always warm up engine before checking clutch adjustment.

Braking System

Hydraulic disc brake maintenance and service procedures.

  1. Brake Fluid: Change annually; DOT 4 recommended
  2. Brake Pads: Replace when thickness below 1.5mm
  3. Brake Discs: Check for warping and minimum thickness
  4. Brake Lines: Inspect for cracks and wear every 6 months
  5. Caliper Service: Clean and lubricate slides every 60 hours

WARNING! Test brakes after service before riding. Never reuse brake fluid.

Regular Maintenance Schedule

Pre-ride inspection and periodic maintenance intervals.

IntervalService Items
Before each rideCheck tire pressure, brakes, controls, fuel level
Every 10 hoursClean air filter, check chain tension
Every 30 hoursChange transmission oil, check spark plug
Every 60 hoursChange fork oil, grease bearings
Every 100 hoursTop end rebuild, suspension service
AnnuallyComplete inspection, brake fluid change

Troubleshooting Guide

Common issues and their solutions for the 1988 KTM 250.

SymptomPossible CauseCorrective Action
Hard startingFouled plug, stale fuelReplace spark plug, drain old fuel
Poor performanceClogged air filter, carb issuesClean air filter, check jetting
Transmission noiseLow oil level, worn gearsCheck oil level, inspect gears
OverheatingLow coolant, water pump failureCheck coolant level, inspect pump
Brake fadeContaminated pads, old fluidReplace pads, flush brake system

Safety Precautions

Always wear proper protective gear including helmet, gloves, boots, and body armor. Never operate motorcycle under influence of drugs or alcohol. Follow all local traffic laws and off-road regulations.

CAUTION! This motorcycle is designed for experienced riders only. High performance requires proper skill and judgment.

Warranty Information

Original warranty: 6 months from date of purchase for manufacturing defects. Warranty does not cover normal wear items, abuse, or improper maintenance. Contact authorized KTM dealer for warranty claims. Keep maintenance records for warranty validation.

1988 KTM 250 Manual © - All Rights Reserved 2025