Segment:
High-performance, 2-stroke, 4-cylinder snowmobiles.
Key Competitors:
Polaris Indy, Ski-Doo Mach Z, Arctic Cat Thundercat (in their respective performance segments of the era).
Engine Configuration:
Renowned for its powerful, high-revving 4-cylinder 2-stroke engines.
Performance Orientation:
Designed for speed and aggressive riding, often considered a 'muscle sled' of its time.
Manual Utility:
Provides critical technical data for owners and technicians to maintain and repair these complex machines effectively.
Engine:
Complete engine tear down and rebuild, including cylinders, pistons, crankshaft, conrod, valves, carburetor/EFI systems, ignition, lubrication, cooling, exhaust.
Drivetrain:
Clutch systems (primary and secondary), drive shaft, chain case, transmission, reverse gear mechanism.
Suspension:
Front forks, rear suspension (bogey wheels, struts, springs, linkage), swingarm, track system.
Electrical:
Stator, magneto, rectifier, battery charging system, lighting, switches, starter system, ignition system troubleshooting.
Fuel System:
Fuel tank, fuel pump, fuel lines, carburetor (jetting, mixture screw adjustment, cleaning) or EFI components.
Body And Controls:
Handlebars, controls, seat, fenders, plastics, hull, skis, steering system, brake system (hydraulic, pads).
Maintenance:
Regularly scheduled maintenance, fluid changes (coolant, oil), lubrication points, filter replacements.
Troubleshooting:
Comprehensive diagnostic procedures for common issues, error codes, no-spark conditions, starting problems, engine performance issues.
Repair:
Detailed step-by-step instructions for component removal, installation, and repair, including complete engine rebuilds.
Diagnostics:
Wiring diagrams, schematics, troubleshooting charts, symptom-based diagnostics.
Internal Engine Rebuild:
Detailed instructions for piston and ring replacement, crankshaft and connecting rod service, bearing replacement, and cylinder head work.
Carburetor Rebuild:
Step-by-step guides for disassembling, cleaning, inspecting, and reassembling carburetors, including jet size information.
Suspension Overhaul:
Instructions for servicing front forks (oil changes, seal replacement) and rear suspension components.
Depth:
Comprehensive, covering all aspects from basic maintenance to complete engine and drivetrain overhauls.
Resources:
Includes torque specifications, part diagrams, illustrations, exploded views, fluid viscosity recommendations, and performance data.
Wiring Schematics:
Includes detailed electrical system schematics and troubleshooting flowcharts.
Torque Specifications:
Extensive list of torque values for all critical fasteners throughout the snowmobile.
Configuration:
Inline 4-cylinder, 2-stroke
Displacement 800:
794cc (approx.)
Cooling System:
Liquid-cooled
Reed Valves:
Specifications and service procedures for reed valve assemblies.
Power Valves:
Service and maintenance procedures for the engine's exhaust power valve system.
Horsepower Estimate 750:
Estimated 110-120+ HP (varies by tune and model year)
Horsepower Estimate 800:
Estimated 120-130+ HP (varies by tune and model year)
Carburetion:
Multiple Mikuni carburetors (e.g., 38mm or similar twin-plugged Mikuni VM38).
Fuel Injection:
Some later models or variants might have featured EFI; manual covers both carb and potential EFI where applicable.
Oil Type Recommendation:
Requires high-quality 2-stroke snowmobile oil with appropriate viscosity (e.g., SAE 5W-30 or 10W-40 depending on temperature, specified in manual).
System:
CDI (Capacitor Discharge Ignition) with dual spark plugs per cylinder.
Engine Internal Components
Bore Stroke 750:
Specifications available in manual.
Bore Stroke 800:
Specifications available in manual.
Compression Ratio:
Specifications detailed in manual for proper setting.
Oil Change:
Regular 2-stroke oil replenishment for oil injection system or premixing as per manual instructions.
Spark Plug Service:
Recommended inspection and replacement intervals for spark plugs based on mileage or operating hours.
Clutch Maintenance:
Periodic inspection and cleaning of clutch sheaves and weights for optimal performance.
Suspension Lubrication:
Greasing of suspension pivot points and chassis lubrication as per schedule.
Coolant Flush:
Scheduled coolant flush and replacement for the liquid-cooled engine.
Coolant Type:
Ethylene glycol-based antifreeze, typically a 50/50 mix with distilled water. Specific type and capacity in manual.
Brake Fluid:
DOT 3 or DOT 4 hydraulic brake fluid, as specified by Yamaha.
Chain Case Fluid Type:
Specific gear oil type and viscosity required for the chain case, detailed in the manual.
Engine Performance:
Potential for carburetor tuning issues, exhaust power valve sticking, or ignition system problems. Manual provides troubleshooting for these.
Drivetrain Wear:
CVT belt wear, clutch bearing issues, and chain wear are common maintenance points covered in the manual.
Suspension Components:
Wear on suspension bushings, shock absorbers, and bogey wheels; manual guides replacement.
Manufacturer:
Yamaha Motor Corporation, known for its high-performance engines and innovative designs across motorcycles, ATVs, and snowmobiles.
Vmax Lineage:
The VMAX-4 was a significant iteration in Yamaha's snowmobile lineup, emphasizing powerful 4-cylinder engines.
Mountain Max Integration:
The inclusion of the Mountain Max 800 indicates a platform sharing or evolution of the VMAX-4 chassis/engine for mountain-specific models.
Production Years:
VMAX-4 750/800 series produced from early to mid-1990s, with this manual covering the specific 1994-1997 range.
