Definitive Yamaha RS Series RS90, RS90R, RSG90, RST90 - Snowmobile Service & Maintenance Manual (2005-2008)

Yamaha RS90 Series Service Manual - 2005-2006 Edition

This official service documentation provides critical factory procedures for the maintenance and repair of the 973cc four-stroke engine and monocoque chassis systems. Uptime is fundamentally secured by the mandatory synchronization of the triple CVK40 carburetors, a process requiring a vacuum gauge to ensure pressure differentials do not exceed 1.33 kPa (0.19 psi) across all cylinders.

Technical Applicability & Model Generations

Standard Performance Chassis (2005-2006)

• RS90 (RS Vector)
• RS90R (RS Vector ER)
• RS90N (2006 RS Vector)
• RS90NR (2006 RS Vector ER)
• RS90RS (2006 RS Vector GT)
• RS90GT (2006 RS Vector GT)

Mountain & Deep Snow Configurations (2005-2006)

• RS90M (RS Vector Mountain)
• RS90MS (2006 RS Vector Mountain SE)

Utility & Wide Track Platforms (2005-2006)

• RSG90 (RS Viking Professional)
• RSG90GT (2006 RS Viking Professional)

Touring & Multi-Passenger Platforms (2005-2006)

• RST90 (RS Venture)
• RST90TF (RS Venture TF)
• RST90GT (2006 RS Venture GT)

Asset Value & Operational Safety

• Prevent catastrophic sheave failure by adhering to the strictly defined V-belt wear limit of 32.5 mm (1.28 in).
• Eliminate ignition system ambiguity by utilizing the onboard self-diagnosis codes (DIAG) to identify T.P.S. or sensor circuit faults.
• Verify engine health through stabilized compression testing, targeting a standard 1,450 kPa (206 psi) at 400 r/min.

Document Metadata

• Print No: 8ES-28197-10 (Edition Specific)
• Page Count: 650+ Technical Pages
• File Format: Searchable PDF Navigation

Technical Depth & Factory Benchmarks

The manual establishes 11.3:1 compression ratios as the baseline for the liquid-cooled DOHC architecture. Internal engine tolerances are specified with extreme precision, including a maximum cylinder head warpage limit of 0.10 mm (0.0039 in) and intake valve clearances calibrated between 0.15 and 0.22 mm. Technicians must utilize the "TDC mark" on the A.C. magneto rotor for all valve train timing operations to prevent piston-to-valve interference.

Visual Navigation Aids

System architecture is detailed through high-resolution exploded views of the slide rail suspension components and comprehensive electrical circuit diagrams. Routing for the drive chain housing—specifically for models equipped with the reverse gear assembly—includes specific shim sizing (0.5 mm) for brake disc clearance adjustment. Hydraulic brake system maintenance is supported by sectional views of the master cylinder and caliper piston seal orientations.

Table of Contents

• General Information: Machine Identification, Special Tools, and Disassembly Preparation.
• Periodic Inspection and Adjustment: Maintenance Charts, Engine Synchronization, and Chassis Lubrication.
• Chassis: Steering System Alignment, Ski/Ski Runner Replacement, and Double Wishbone Geometry.
• Power Train: Primary and Secondary Sheave Service, Drive V-Belt Calibration, and Track Tensioning.
• Engine: Cylinder Head Overhaul, Camshaft Installation, and Crankshaft/Balancer Shaft Specs.
• Cooling System: Thermostat Testing, Water Pump Seal Installation, and Heat Exchanger Routing.
• Carburetion: CVK40 Separation, Float Height Settings, and T.P.S. Voltage Calculations.
• Electrical: Ignition Troubleshooting, Starter Motor Service, and Self-Diagnosis Code Tables.
• Specifications: General Dimensions, Tightening Torque Sequences, and Cable Routing Diagrams.

Operational Limits & Specifications

• Engine Idle Speed: 1,300 – 1,500 r/min.
• Primary sheave Engagement: 2,800 – 4,200 r/min (Model Variant Specific).
• Fluid Requirements: 0W-30 API SE/SF/SG Engine Oil; DOT 4 Brake Fluid.
• Spark Plug Gap: 0.7 – 0.8 mm (NGK CR8E).
• Torque Sequence: A.C. Magneto Rotor Bolt at 130 Nm (94 ft-lb); Cylinder Head Cover at 12 Nm.