Yamaha Ovation 340, CS340 Snowmobile 1989–1999 Maintenance & Repair Manual

• Covers CS340N/85L, electric-start CS340EN/85N, and European CS340/85M configurations, with frame and engine starting numbers 85L-000101, 85N-000101, and 85M-000101.
• Documents engine removal and internal overhaul, including cylinder, piston, crankshaft, CDI magneto, oil-pump, reassembly, installation, and recoil-starter repair procedures.
• Covers TEIKEI Y30W-2 carburetor service and tuning, oil-pump stroke adjustment and bleeding, altitude jetting, clutch tuning, gearing selection, and slide-rail suspension setup.
• Details primary and secondary sheaves, drive V-belt, drive-chain housing, brake, track, slide-rail suspension, front axle, steering, skis, and telescopic front suspension, with the related removal, inspection, repair, and adjustment procedures.
• Includes separate U.S./Canada and Europe wiring diagrams, ignition no-spark diagnostics, CS340EN starter and charging fault charts, lighting and signal troubleshooting, electrical tests, and cable-routing drawings.
• The 252-page Yamaha service manual PDF provides maintenance schedules, lubrication charts, model-specific torque tables, wear and clearance limits, exploded assembly views, and Yamaha special-tool numbers.

Model and Configuration Coverage

Coverage is organized by Yamaha model code and starting serial number. The CS340N/85L uses recoil starting, while the CS340EN/85N adds an electric starter, battery, charging circuit, and the related inspection and repair procedures. The European CS340/85M receives its own circuit diagram and cable-routing drawings, along with market-specific component notes such as the right-hand brake arrangement. These identifiers make it possible to match the publication to the machine before parts, wiring, or adjustment data are selected.

The general specifications identify the platform as a fan-cooled, two-stroke parallel twin with piston-valve induction, Yamaha Autolube, a TEIKEI carburetor, automatic V-belt clutching, chain secondary drive, a slide-rail rear suspension, telescopic-strut front suspension, and a caliper-type disc brake.

Maintenance and Technical Scope

The maintenance chapter covers storage and pre-season preparation, periodic service and lubrication schedules, body-panel and control access, throttle and starter cable adjustment, oil-pump cable and stroke setting, oil-system bleeding, filter and fuel-pump inspection, drive-belt checks, sheave distance and offset, chaincase oil and chain slack, brake adjustment, track tension and alignment, ski setup, ignition timing, lighting, and CS340EN battery service.

The tuning section extends beyond basic carburetor adjustment. It includes standard and high-altitude carburetor charts, fresh-air-intake settings, low-, middle-, and high-speed tuning, clutch engagement and shifting setup, drive/driven gear selection, slide-rail stopper-band and spring-preload settings, and a high-altitude diagnostic flowchart that ties jetting, gearing, and clutch changes together.

The engine chapter covers removal, disassembly, inspection, repair, reassembly, and installation of the intake and exhaust manifolds, oil pump, cylinder head, cylinders, pistons, rings, piston pins, crankcase, crankshaft, CDI magneto, and recoil starter. Inspection sections provide bore and piston measurements, ring and pin limits, crankshaft runout and bearing checks, cylinder-head warpage inspection, sealing-surface checks, and assembly-specific torque and lubrication data.

Power-train and chassis coverage includes primary-sheave and drive V-belt overhaul, secondary-sheave service, drive-chain housing removal and inspection, brake disassembly, slide-rail suspension repair, front axle and track service, steering-column and relay-rod work, ski removal and alignment, and front-suspension disassembly and inspection.

Specifications and Diagnostic Data

The electrical chapter separates the CS340N/CS340EN U.S./Canada circuit diagram from the CS340 Europe circuit diagram. It also includes electrical-component location views, connection and switch tests, bulb checks, throttle-override switch diagnosis, an ignition-system “no spark or weak spark” troubleshooting chart, a CS340EN “starter motor does not operate” chart, a CS340EN “battery is not charged” chart, lighting and brake-light fault charts, and model-specific cable-routing drawings.

The appendices consolidate engine, power-train, chassis, and electrical specifications; tightening-torque tables; definitions of units; and cable-routing layouts. The special-tool section identifies factory tools by number, including the Sheave Gauge YS-91047, Piston Pin Puller YU-01304 / 90890-01304, Primary Sheave Puller YS-01882-A / 90890-01898, Clutch Spider Separator YS-28890-A / 90890-01711, Pocket Tester YU-03112 / 90890-03112, and Dynamic Spark Tester YM-34487 / 90890-03144.

Manual-Specific Repair Notes

The primary-sheave spider uses a left-hand thread, and the spider, cap, and roller hardware must retain their specified alignment and orientation; forcing the spider in the normal direction or mixing indexed parts can damage the clutch and upset balance. During crankcase assembly, the oil-seal lip must seat in its groove and the crankshaft must remain free before final tightening, since a displaced seal or bound crank can be damaged as the case halves are drawn together. Cylinder-head removal and installation use staged loosening and a crisscross tightening pattern to reduce distortion and sealing problems.

Snowmobile repair involves a supported chassis, spring-loaded clutch and recoil components, rotating track and driveline parts, gasoline and oil systems, and battery acid on the CS340EN. Secure the machine, isolate electrical power, and follow the manual’s warnings and specified service tools before disassembly or live testing.