Yamaha Enticer II 570 EX570R, EX570ER, EX570T, EX570ET, EX570STT & EX570SXT Snowmobile - Authorized Factory Service & Repair Guide (1991-1993)

Yamaha Enticer II 570 Series Snowmobile Service Manual - 1991-1993

This factory-authorized documentation provides the definitive system architecture and diagnostic procedures for the 569cc liquid-cooled propulsion systems. Precise engine synchronization is maintained via the mandatory vacuum gauge calibration of the Mikuni VM38 and TM38 carburetion circuits. Utilizing Yamalube 2-cycle oil as the specified lubricant ensures optimal lubrication of the Autolube separate lubrication system, which is critical for preventing piston seizure and maximizing engine uptime.

Technical Applicability & Serial Ranges: Model Identification

The following model series are identified by the first three digits of the Frame/Engine ID. Technical data and maintenance intervals within this manual apply specifically to these machine prefixes:

Standard Configuration Models

• 88R Series: EX570R Enticer II 570 (1991-1993)
• 88S Series: EX570ER Enticer II 570 (with Electric Start) (1991-1993)

Extended Series & Specialty Variants

• 8AV Series: EX570T Enticer II 570
• 8AW Series: EX570ET Enticer II 570
• 89L Series: EX570STT Enticer II 570 ST
• 8AY Series: EX570SXT Enticer II 570 SX

Operational Performance Benchmarks

• Maintenance ROI: Adherence to the periodic maintenance table significantly reduces the requirement for high-cost engine overhauls by identifying wear in the slide runners and drive V-belts before catastrophic failure.
• Safety Critical Systems: Verification of the Throttle Override System (T.O.R.S.) ensures ignition interruption occurs if the carburetor fails to return to the idle position, preventing unintended machine movement.
• System Integrity: Factory torque sequences for cylinder heads and crankcase bolts prevent warping and ensure vacuum-tight seals in the 2-stroke induction path.

Technical Document Metadata

• Document Type: Authorized Factory Service & Repair Guide
• Page Count: 439 Pages
• Searchability: Fully indexed and text-searchable (OCR)

Calibration Data & Factory Benchmarks

Engine performance is regulated through strict adherence to the following clearances and settings. Piston-to-cylinder clearance must be maintained between 0.070–0.075 mm (0.0028–0.0030 in) to ensure thermal expansion does not lead to seizure under high-load operations. Ignition timing is fixed at 16° B.T.D.C. at specified RPM benchmarks.

Diagnostic Visual Aids & Navigation

The manual utilizes illustrated thumb tabs for rapid cross-referencing between mechanical and electrical subsystems:

• System Schematics: Detailed wiring diagrams for EX570R and EX570ER models including starter relay and charging circuits.
• Cable Routing: Geometric mapping for throttle, oil pump, and brake cable paths to prevent binding or freezing during steering maneuvers.
• Exploded Views: Illustrated symbols indicating the precise application points for Loctite, molybdenum disulfide oil, and low-temperature lithium soap-base grease.

Table of Contents

• Chapter 1: General Information (Machine Identification, Special Tools)
• Chapter 2: Periodic Inspections and Adjustments (Maintenance Table, Engine/Chassis/Electrical Tuning)
• Chapter 3: Chassis (Steering, Ski, Front Suspension)
• Chapter 4: Power Train (Primary/Secondary Sheave, Drive Chain, Brake, Track)
• Chapter 5: Engine Overhaul (Disassembly, Inspection, Repair, Assembly)
• Chapter 6: Cooling System (Coolant Flow, Water Pump, Heat Exchanger)
• Chapter 7: Carburetion (Mikuni VM38/TM38 Service, Fuel Pump)
• Chapter 8: Electrical (Ignition, Lighting, Starting System, T.O.R.S.)
• Chapter 9: Appendices (General/Maintenance Specifications, Cable Routing)

Operational Limits & Critical Specifications

System reliability depends on the application of specific factory tolerances and fluid types:

• Torque Sequence: Cylinder Head Bolts: 20 Nm (Initial) -> 28 Nm (Final).
• Fluid Capacities: Cooling System: 4.2 L (4.4 US qt); Oil Tank: 3.0 L (3.2 US qt); Drive Chain Housing: 250 cm³ (8.5 US oz).
• Transmission Parameters: Clutch engagement speed is set to approximately 3,800 RPM with a secondary sheave standard twist angle of 50°.
• Lubrication Specification: ESSO Beacon 325 or Aeroshell Grease #7A for suspension and steering pivot points.