Positioning:
A critical resource for owners and mechanics of classic Jawa motorcycles, particularly the popular 250cc and 350cc models. Essential for maintaining and restoring these historically significant machines.
Competitors:
This manual competes with other third-party reproduction manuals or original, often hard-to-find, factory service documentation for classic Eastern Bloc motorcycles. Its instant digital availability is a key differentiator.
Features:
Comprehensive coverage of all models, instant download in PDF, detailed diagrams and illustrations, step-by-step instructions, and extensive technical specifications for repair and maintenance.
Diagrams Illustrations:
Features numerous exploded views and diagrams crucial for visual identification of parts and understanding assembly sequences.
Engine:
Complete engine disassembly, assembly, tuning, and troubleshooting for 250cc and 350cc two-stroke engines. Includes lubrication, cooling, and ignition systems.
Transmission:
Detailed procedures for gearbox inspection, maintenance, repair, and adjustment. Includes clutch assembly and operation.
Chassis:
Front fork (telescopic), rear suspension (swingarm with twin shock absorbers), frame inspection and repair, steering head bearing service.
Brakes:
Drum brake system maintenance, adjustment, and component replacement for both front and rear brakes.
Electrical System:
Wiring diagrams, lighting system service, ignition coil and points replacement, dynamo/generator (if applicable) testing and repair, horn, and switches.
Fuel System:
Carburetor identification, disassembly, cleaning, adjustment, and jetting. Fuel tank, fuel lines, and petcock service.
Wheels Tires:
Spoke wheel maintenance, tire pressure recommendations, tube replacement, and wheel bearing service.
Bodywork:
Fender removal and installation, seat maintenance, fuel tank removal and cleaning, and general panel alignment.
Maintenance:
Regular servicing, oil changes (for gearbox), spark plug replacement, chain adjustment, brake adjustments, and general lubrication.
Troubleshooting:
Systematic diagnostic procedures for common starting issues, engine misfires, transmission problems, and electrical faults.
Repair:
Step-by-step instructions for component replacement, overhaul, and repair of all major motorcycle systems.
Overhaul:
Complete engine and gearbox overhaul procedures, including piston and ring replacement, cylinder honing, crankshaft bearing replacement, and gear inspection.
Adjustment:
Precise instructions for clutch, throttle, and brake cable adjustments, ignition timing, and carburetor idle speed.
Engine Rebuild:
Includes full engine strip-down, cleaning of all internal components, replacement of wear items (piston, rings, bearings, seals), cylinder inspection and potential re-boring/honing, crankshaft alignment checks.
Carburetor Rebuild:
Detailed steps for disassembling, cleaning, and reassembling carburetors, including identification and replacement of jets, needles, floats, and seals. Critical for proper fuel mixture and engine operation.
Ignition Timing Adjustment:
Instructions on setting ignition timing using points and a feeler gauge or timing light (if specified for the model) to ensure optimal combustion and engine performance.
Wheel Truing:
Guidance on spoke tension adjustment and wheel alignment for maintaining wheel integrity and smooth riding.
Depth:
Comprehensive, covering from basic user maintenance to complete engine and gearbox rebuilds, suitable for both amateur and professional mechanics.
Diagnostic Charts:
Likely includes troubleshooting charts that correlate symptoms (e.g., engine not starting, poor acceleration) with potential causes and corrective actions.
Tolerance Specifications:
Provides critical measurement specifications for engine components such as piston-to-cylinder clearance, bearing clearances, and gear backlash, essential for rebuild accuracy.
Engine Type:
Two-stroke, air-cooled, parallel twin (for 350cc models), single-cylinder (for 250cc models)
Bore Stroke 250:
Typically around 63 mm x 80 mm (check specific model variants)
Bore Stroke 350:
Typically around 60.5 mm x 65 mm (check specific model variants)
Compression Ratio Approx:
Around 7.0:1 to 8.0:1 (varies by model and tuning)
Horsepower 250 Approx:
Around 16-20 hp (varies by model and tuning)
Horsepower 350 Approx:
Around 20-24 hp (varies by model and tuning)
Carburetor Type:
Typically Jikov or similar; single or twin carburetors depending on the model. Specific model carburetor identification and jetting data will be in the manual.
Fuel Type:
Leaded or Unleaded gasoline with appropriate 2-stroke oil mix (e.g., 1:25 or 1:50, manual will specify).
Gearbox Oil Type:
GL-4 or GL-5 hypoid gear oil, SAE 80W/90. Specific Jawa recommendations will be detailed.
Tune Up Interval Approx:
Every 3,000-5,000 km (engine tune-up, points, spark plug, carb adjustment). Manual will provide specific intervals.
Gearbox Oil Change:
Every 5,000-10,000 km. Manual will specify exact mileage and procedure.
Gearbox Oil Capacity:
Approximately 0.5 - 0.75 liters (check manual for exact capacity and level checking procedure).
Fork Oil Type:
Likely a 10W or 15W fork oil. Manual will specify type and quantity per leg.
Ignition Points:
Points and condenser wear, requiring regular cleaning and gap adjustment for optimal performance.
Carburetor Clogging:
Jikov carburetors can be sensitive to fuel quality and can become clogged, leading to poor running. Regular cleaning is often necessary.
Clutch Drag:
Can occur due to wear or improper adjustment of the clutch plates or cable. Manual details proper adjustment and replacement.
Electrical Connections:
Corrosion or looseness in electrical connections can lead to intermittent faults. Manual provides wiring diagrams for diagnosis.
