Yamaha Ovation 340 / CS340 Snowmobile Service Manual, 1989–1999

This Yamaha service manual covers the Ovation CS340N, electric-start CS340EN, and European CS340 configurations. It documents maintenance, engine overhaul, chassis repair, and electrical diagnosis for the fan-cooled, piston-valve two-stroke twin with Yamaha Autolube.

PDF Search, Bookmarks and Diagram Detail

Navigation and wiring labels: PDF text search is not available. Embedded bookmarks provide access to chapters and major service sections. Small wire-color codes and connector labels in the larger wiring diagrams require zooming for comfortable reading.

One printable, English-language PDF contains 252 pages, including the two opening symbol-guide and index pages, chapter contents pages, three memo pages, and two final wiring-diagram sheets.

Engine Overhaul, Drivetrain Service and Electrical Diagnosis

The following highlights are selected contents, rather than a complete table of contents; other topics include headlight-beam adjustment and body-panel access.

• Engine repair: Step-by-step procedures for engine removal, internal inspection, crankcase assembly, cylinder and piston installation, CDI magneto service, and recoil-starter repair.

• Carburetion and lubrication: TEIKEI carburetor disassembly, cleaning, float inspection, oil-pump stroke adjustment, oil-system bleeding, and fuel-pump operation checks.

• Operating-condition tuning: Altitude and temperature jetting charts, fresh-air-intake settings, clutch tuning, gearing selection, and slide-rail suspension setup.

• Clutch and chain drive: Primary and secondary sheave service, drive V-belt inspection, drive-chain housing repair, chain adjustment, and disc-brake service.

• Track and chassis: Slide-rail suspension disassembly, wheel-bearing replacement, front axle and track removal, steering repair, ski alignment, and telescopic front-suspension inspection.

• Electrical troubleshooting: Separate U.S./Canada and Europe circuit diagrams, ignition fault charts, CS340EN starter and charging tests, lighting diagnosis, and cable-routing drawings.

Suited to mechanics familiar with two-stroke engine work and electrical testing, with access to the measuring equipment and special tools specified for the procedures.

Model and Market Differences

The CS340N/85L uses recoil starting; the CS340EN/85N adds an electric starter, battery, and associated charging circuit. The European CS340/85M has its own circuit diagram and cable-routing drawings, with market-specific details including 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 North American ignition sections cover the throttle override system and its throttle and carburetor switches; European diagnosis includes the tether switch.

Maintenance and Operating-Condition Tuning

Periodic maintenance and lubrication tables accompany storage and pre-season preparation guidance. Service procedures address throttle, starter and oil-pump cables, filters, sheave distance and offset, chaincase oil, brake adjustment, track alignment, ski setup, ignition timing, and CS340EN battery inspection.

The tuning section distinguishes standard and fresh-air-intake jetting, with separate low-speed and midrange/high-speed guidance. Its high-altitude troubleshooting flowchart connects carburetor settings with gearing and clutch behavior, helping organize diagnosis when operating conditions change.

Stopper-band positions and spring-preload settings are explained in relation to handling, rider weight, and course conditions.

Internal Engine Inspection and Assembly

Inspection coverage includes cylinder-head warpage and resurfacing, bore and piston measurements, piston-ring and pin checks, crankshaft runout, connecting-rod clearances, bearings, sealing surfaces, and oil-pump drive gears.

Exploded views for the crankcase and crankshaft, cylinder and cylinder head, and recoil starter support the assembly instructions. Component-specific torque and lubrication data accompany the work, including staged cylinder-head loosening and crisscross tightening.

The crankcase assembly notes address oil-seal seating and crankshaft freedom before final tightening: a displaced seal or binding crankshaft can be damaged as the case halves are secured.

Sheaves, Track and Suspension Repair

Primary-sheave instructions cover bushings, weights, rollers, sliders, spring compression, match marks, and roller-bolt orientation. The spider has a left-hand thread; incorrect tool support or forcing it in the wrong direction can crack or damage the spider and sheaves.

Chaincase procedures extend to sprockets, bearings, seals, and the tensioner. Suspension and track coverage includes wheel-bearing replacement, slide-runner wear, shock inspection, front-axle bearings, drive sprockets, and track installation direction.

Steering-column, relay-rod, tie-rod, ski-runner, and telescopic-strut procedures include their related inspection and assembly requirements.

Fault Charts and Workshop References

The electrical chapter includes a “no spark or weak spark” chart, a CS340EN “starter motor does not operate” chart, and a CS340EN “battery is not charged” chart. Lighting and signal diagnosis separates bulbs, sockets, switches, coils, wiring connections, and regulator faults.

Starter-motor coverage goes beyond circuit checks to disassembly, commutator inspection, armature testing, brush wear, and reassembly. Electrical-component location views, switch-connection charts, and market-specific cable-routing drawings support fault tracing.

The appendices collect engine, power-train, chassis, and electrical specifications, tightening-torque tables, and definitions of units. Listed Yamaha tools include 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.

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.

A Preview of Engine Clearance and Charging-Test Data

For the covered engine, piston-to-cylinder clearance is specified at 0.040–0.045 mm, with a 0.1 mm service limit. These figures accompany the cylinder and piston inspection information.

The CS340EN charging-system fault chart specifies 14–15 V at 5,000 r/min, measured at the battery. It links the voltage check with charging-coil and wiring tests.