Product Segment:
High-performance sport motorcycle of its era.
Target Audience:
Enthusiasts and owners seeking to maintain and repair their Moto Guzzi 850 Le Mans I or II.
Comparable Models:
Ducati 900SS, BMW R100S, Laverda Jota.
Design Philosophy:
Emphasis on Italian performance, distinctive V-twin character, and sporting intent.
Manual Value Proposition:
Essential resource for preserving the originality and performance of a classic Italian motorcycle.
General Coverage:
Comprehensive service and repair for Moto Guzzi 850 Le Mans I and II models.
Specific Systems:
Engine, transmission, drivetrain, suspension, brakes, electrical system, fuel system, exhaust, chassis, bodywork.
Estimated Pages:
300-400 pages (typical for comprehensive workshop manuals of this era).
Type:
Workshop Manual / Service Manual / Repair Manual
Format:
Likely Printed (original factory documentation or professional reproduction). May exist as PDF scan.
Engine:
Detailed breakdown of the 844cc V-twin engine, including cylinder head, valve train, piston/rod assembly, crankshaft, lubrication system, cooling system (air-cooled), and timing.
Fuel System:
Carburetor tuning and overhaul (likely Dell'Orto PHM 40 or similar), fuel pump operation, fuel tank and lines.
Transmission:
5-speed gearbox servicing, clutch operation and adjustment, final drive and shaft drive maintenance.
Brakes:
Front and rear brake system maintenance, including hydraulic lines, master cylinders, calipers (likely Brembo), and disc pads.
Suspension:
Front fork servicing (likely Marzocchi or similar), rear shock absorber adjustment and replacement, swingarm and bearing maintenance.
Electrical System:
Wiring diagrams, ignition system (points or electronic), lighting, charging system (alternator/generator), starter motor, battery care.
Chassis Frame:
Frame inspection, headstock bearings, wheel bearings, steering head maintenance.
Bodywork Fittings:
Fairing removal and installation, seat, fuel tank, fenders, and ancillary fittings.
Routine Maintenance:
Oil changes, filter replacements, spark plug servicing, chain adjustment (if applicable, though shaft drive is more common), lubrication points.
Diagnostic Troubleshooting:
Step-by-step guides for identifying and rectifying common mechanical and electrical faults.
Major Repairs:
Engine rebuild procedures, transmission overhauls, suspension component replacement, brake system bleeding and component replacement.
Technical Specifications:
Detailed torque values, clearances, fluid capacities, and electrical specifications.
Depth Of Coverage:
Comprehensive from basic rider maintenance to full engine and gearbox rebuilds. Suitable for professional mechanics and experienced enthusiasts.
Diagnostic Level:
Advanced diagnostics, including troubleshooting intermittent faults and electrical issues.
Format:
Likely Printed Paper. If digital, typically PDF.
Print Quality:
Original factory quality (clear diagrams, legible text). If scanned, quality varies but should be legible.
Binding:
Typically perfect bound or stapled for printed versions. PDF is digital.
Paper Type:
Durable paper stock, often glossy or semi-gloss for diagrams in original prints.
Engine Type:
Air-cooled, four-stroke, 90-degree V-twin (longitudinal)
Displacement:
844 cc (844cc)
Bore X Stroke:
90 mm x 66 mm (approximate)
Compression Ratio:
9.0:1 to 10.0:1 (depending on specific Le Mans version)
Valve Train:
OHV (pushrod actuated), 2 valves per cylinder
Horsepower:
Approx. 77-80 HP @ 7000-7500 RPM (Le Mans I/II)
Torque:
Approx. 70-75 Nm @ 6000 RPM (Le Mans I/II)
Carburetors:
2 x Dell'Orto PHM 40 (or similar performance-oriented carburetors)
Fuel Type:
Unleaded gasoline (91 RON minimum recommended, higher octane for performance)
Type:
5-speed constant mesh gearbox
Drive:
Shaft drive to rear wheel
Clutch:
Single dry plate clutch (Le Mans I), potentially twin plate clutch on some later models or variations.
Gear Ratios:
Specific ratios detailed within the manual for optimal performance.
Safety Standards:
N/A (Motorcycle, not subject to car safety ratings of the era).
Braking System:
Dual front disc brakes (typically Brembo), single rear disc brake. High-performance braking setup for its time.
Frame Construction:
Steel tube frame for rigidity and stability.
Infotainment System:
N/A (Classic motorcycle, no infotainment system).
Driver Assistance Features:
N/A (Classic motorcycle).
Connectivity Features:
N/A (Classic motorcycle).
Instrument Cluster:
Analog speedometer, tachometer, oil pressure light, neutral indicator, turn signal indicators. Often includes voltmeter.
Oil Change Interval:
Typically every 5,000 km or annually.
Valve Clearance Check:
Every 10,000-15,000 km.
Gearbox Oil Change:
Every 10,000 km or annually.
Engine Oil Type:
SAE 20W-50 or 10W-50 motorcycle-specific oil, API SF or SG rating (refer to manual for exact spec).
Engine Oil Capacity:
Approx. 2.75 - 3.0 liters (with filter change).
Gearbox Oil Type:
Hypoid gear oil, SAE 80W-90 (refer to manual for exact spec).
Brake Fluid Type:
DOT 4 brake fluid.
Common Wear Items:
Clutch wear, carburetor synchronization issues, occasional electrical gremlins, aging fuel lines, and fork seal leaks.
Engine Notes:
While generally robust, proper maintenance of the Guzzi V-twin is crucial for longevity. Valve adjustments are critical.
Moto Guzzi Legacy:
Long history of producing distinctive Italian motorcycles, known for their V-twin engines and shaft drive.
Le Mans Development:
Developed from the Moto Guzzi 850 T and T3 models, featuring upgraded components for enhanced performance and sportier ergonomics.
Le Mans I Features:
Introduced in 1976, featured a sportier chassis, revised engine tuning, and distinctive fairing.
Le Mans Ii Features:
Introduced in 1978, featured a larger fuel tank, updated braking system (often larger discs), and minor engine refinements.
Manufacturing Location:
Mandello del Lario, Italy
Production Period:
1976-1984 (Le Mans I & II)
