2005–2008 Yamaha RS90 Series Snowmobile Service Manual Set

The supplements provide model-specific service information and refer back to the numbered base chapters for shared procedures. Match the model code and regional version when selecting the applicable specifications and assembly instructions.

Searchable Text, Bookmarks and Wiring Detail

Search and diagram access: Text search is available in the base manual and both supplements. Embedded bookmarks cover chapters and major assemblies, although several introductory entries have no working destination. Small labels on the full-page wiring diagrams require zooming.

All three publications are combined in one printable, 650-page PDF. The publication totals above already include nine index and contents pages: five in the base manual and two in each supplement.

Engine, Clutch and Snowmobile Chassis Service

The topics below are a selection of the documented work. Other sections cover backrest and passenger-seat removal and speedometer-unit inspection.

• Engine repair: Engine removal and installation, camshaft and valve service, crankcase disassembly, and inspection of pistons, connecting rods, crankshaft and balancer shaft.

• Clutches and drive system: Primary and secondary sheave disassembly, bushing inspection, drive V-belt adjustment, and chaincase service for reverse and non-reverse configurations.

• Carburetion: CVK40 carburetor inspection, synchronization and fuel-level adjustment, plus fuel-pump testing and Throttle Position Sensor (T.P.S.) inspection.

• Cooling system: Heat-exchanger inspection, thermostat testing, water-pump disassembly, seal replacement and cooling-system bleeding.

• Brakes and chassis: Hydraulic brake bleeding, caliper and master-cylinder service, steering alignment, ski inspection, and slide rail suspension removal and assembly.

• Electrical diagnosis: Ignition, starting and charging troubleshooting, Throttle Override System (T.O.R.S.) checks, self-diagnosis tables, wiring diagrams and cable-routing views.

This material is suited to mechanics with snowmobile repair experience and access to the specified pullers, alignment tools and electrical test equipment.

Engine Inspection and Carburetor Setup

The engine chapters go beyond routine maintenance. They cover cylinder-head inspection, valve-guide and valve-seat work, crankshaft bearing selection, and clearance checks using Plastigauge. Valve-pad selection tables support valve-clearance adjustment, while assembly illustrations identify timing marks and component orientation.

A.C. magneto rotor and starter-clutch service, oil-pump inspection and crankcase assembly are also documented. Component-specific torque tables accompany the engine work.

Step-by-step instructions cover carburetor synchronization and fuel-level adjustment. Main jet selection charts, gear ratio charts and high altitude tuning charts provide configuration-specific reference data rather than a single setting for every operating condition.

Primary Sheave, Brakes and Suspension

The primary clutch spider has a left-hand thread. Its service section warns that inadequate support during removal or tightening can crack the sheaves or spider; it identifies the clutch spider separator YS-28890-C and clutch separator adapter YS-34480.

Chaincase instructions distinguish reverse and non-reverse assemblies and include secondary-shaft installation and brake-disc clearance adjustment. The brake sections cover pad replacement, piston and seal inspection, master-cylinder assembly and hydraulic bleeding.

Model-specific exploded views distinguish the slide rail suspension layouts. Adjustment information covers stopper bands, control rods, spring preload, damping force and applicable two-up settings, alongside track tension and ski alignment.

Securely support the snowmobile and keep clear of the rotating track. Follow the manual’s battery-isolation requirements for the service work being performed.

Electrical Tests and Fault Tracing

Ignition and charging circuit diagrams accompany symptom-based troubleshooting charts. For a no-spark complaint, the ignition section links the symptom to checks of coils, switches, the throttle position sensor and wiring, helping technicians narrow the fault before selecting replacement parts.

Separate sections address grip and thumb warmers, passenger grip warmers where fitted, and carburetor heaters. Self-diagnosis tables explain displayed fault indications, while connector views and cable-routing illustrations show the associated harness arrangements.

Selected Valve-Clearance and Assembly Specifications

Engine reference data includes a cold intake-valve clearance of 0.15–0.22 mm and a spark-plug torque specification of 13 N·m. The camshaft-cap section lists 10 N·m for the cap bolts, together with staged-tightening precautions.

For primary-sheave assembly, the spider specification is 200 N·m. The associated procedure identifies the locking-agent requirements and special holding tools.