Yamaha SR125 98 - User Manual

This document serves as a supplementary service manual for the Yamaha SR125 '98 motorcycle, providing essential information for its maintenance and repair. It is designed to be used in conjunction with the SR125 '97 Service Manual (3MW-AE1) for comprehensive service procedures. The manual is structured to guide mechanics through various aspects of the motorcycle, from general information and identification to detailed specifications and periodic maintenance schedules.

The manual begins with a "FOREWORD" that clarifies its purpose as an addendum to the main service manual, introducing new service data specific to the '98 model. It emphasizes the necessity of using both manuals for complete information. The copyright information indicates that the manual was published by Yamaha Motor Co., Ltd. in July 1997, with all rights reserved, prohibiting unauthorized reproduction or use.

An "IMPORTANT INFORMATION" section highlights critical safety and procedural notations. The Safety Alert Symbol (an exclamation mark within a triangle) signifies "ATTENTION! BECOME ALERT! YOUR SAFETY IS INVOLVED!", underscoring the importance of safety during service. "WARNING" instructions are crucial, as failure to follow them could result in severe injury or death to the operator, bystanders, or service personnel. "CAUTION" notes indicate special precautions to prevent damage to the motorcycle, while "NOTE" provides key information to simplify or clarify procedures.

The "HOW TO USE THIS MANUAL" section details its construction and format. It explains that the manual is organized into chapters, each identified by a symbol on the upper right of the page. Titles are hierarchical, with 1st, 2nd, and 3rd titles guiding the user through the content. Procedures are presented in a sequential, step-by-step format, designed for easy readability and reference. Important procedures are marked with asterisks, and specific data or special tools are framed in boxes with relevant symbols. Encircled numerals denote part names, while alphabetical letters indicate data or alignment marks. A condition of a faulty component is followed by an arrow symbol and the required course of action. Exploded diagrams are included before each disassembly section to aid in identifying correct procedures for both disassembly and assembly.

"ILLUSTRATED SYMBOLS" are extensively used throughout the manual to enhance clarity and ease of navigation. Thumb tabs (symbols 1 to 8) indicate chapter numbers and content, covering General Information, Specifications, Periodic Inspection and Adjustment, Engine, Carburation, Chassis, Electrical, and Troubleshooting. Additional symbols (9 to 16) identify specifications within the text, such as maintainability with the engine mounted, fluid filling, lubricants, special tools, tightening torques, wear limits/clearances, engine speed, and electrical measurements (Ω, V, A). Furthermore, symbols (17 to 22) in exploded diagrams specify types of lubricants and lubrication points, including engine oil, gear oil, molybdenum disulfide oil, wheel bearing grease, lightweight lithium-soap base grease, and molybdenum disulfide grease. Symbols (23 and 24) indicate where to apply locking agent (LOCTITE®) and when to use new parts, respectively.

The "CONTENTS" section provides an overview of the manual's structure, listing main categories such as "GENERAL INFORMATION," "SPECIFICATIONS," and "PERIODIC INSPECTIONS AND ADJUSTMENT." Each category is further broken down into sub-sections, allowing users to quickly locate specific information.

Under "GENERAL INFORMATION," the "MOTORCYCLE IDENTIFICATION" section is crucial for proper identification and ordering of spare parts. It explains that the frame serial number is stamped on the right side of the frame, and the engine serial number is stamped on the crankcase. A "NOTE" reminds users that designs and specifications are subject to change without notice. The model label, affixed under the seat, provides essential information for ordering parts.

The "SPECIFICATIONS" chapter details general and maintenance specifications for the SR125 '98. This includes model code, dimensions (overall length, wheelbase), chassis parameters (caster angle, trail), and electrical system details (generator type, headlight bulb wattage). Maintenance specifications cover chassis components like front suspension oil capacity and level, and electrical components such as ignition coil winding resistance, charging system type, electric starter armature coil resistance, brush spring pressure, and relay models/manufacturers.

The "PERIODIC INSPECTIONS AND ADJUSTMENTS" chapter is fundamental for ensuring the motorcycle's reliability and longevity. The "INTRODUCTION" emphasizes that following these preventive maintenance procedures will reduce the need for costly overhaul work and is applicable to both new and in-service vehicles. All service technicians are expected to be familiar with this chapter.

The "PERIODIC MAINTENANCE/LUBRICATION INTERVALS" table is a comprehensive guide for routine service. It lists various items, their inspection routines, and the recommended service intervals (Brake-in 1,000 KM, 6,000 km or 6 months, and 12,000 km or 12 months, with some items requiring service every 500 km). Items marked with an asterisk (*) are recommended to be serviced by a Yamaha dealer.

Key maintenance routines include:

• Fuel line: Checking for cracks or damage and replacing if necessary.
• Spark plug: Checking condition, cleaning, regapping, or replacing.
• Valves: Checking and adjusting valve clearance.
• Cam chain: Checking and adjusting chain tension.
• Air filter: Cleaning or replacing.
• Battery: Checking electrolyte level and specific gravity, correcting or recharging, and ensuring proper breather hose routing.
• Clutch: Checking operation, adjusting, or replacing the cable.
• Front brake: Checking operation, fluid level, fluid leakage, and replacing brake pads if necessary.
• Rear brake: Checking operation, adjusting cable, replacing brake shoes if necessary, and rebalancing or replacing.
• Wheels: Checking balance, runout, spoke tightness, and for damage; tightening spokes and rebalancing or replacing if necessary.
• Tires: Checking tread depth and for damage, replacing if necessary, and correcting air pressure.
• Wheel bearings: Checking for looseness or damage and replacing if necessary.
• Swingarm: Checking pivoting point for play and correcting if necessary.
• Drive chain: Checking and adjusting slack, ensuring rear wheel alignment, and cleaning and lubricating. This is a frequent maintenance item, recommended every 500 km.
• Steering bearings: Checking bearing play and steering for roughness, correcting accordingly, and lubricating with lithium soap base grease every 24,000 km or 24 months (whichever comes first).
• Chassis fasteners: Ensuring all nuts, bolts, and screws are properly tightened and tightening if necessary.
• Sidestand/centerstand: Checking operation, lubricating, and repairing if necessary.
• Sidestand switch: Checking operation and replacing if necessary.
• Front fork: Correcting accordingly, and replacing shock absorber assembly if necessary.
• Rear shock absorber assemblies: Checking operation and for oil leakage, and replacing shock absorber assembly if necessary.
• Carburetor: Checking engine idling speed and starter operation, adjusting if necessary, and checking oil level and for oil leakage.
• Engine oil: Correcting if necessary, and changing (warm engine before draining).
• Engine oil filter element: Cleaning or replacing if necessary.

A "NOTE" specifically addresses brake fluid replacement:

1. When disassembling the master cylinder or caliper cylinder, replace the brake fluid. Normally, check the brake fluid level and fill as required.
2. On the inner parts of the master cylinder and caliper cylinder, replace the oil seals every two years.
3. Replace the brake hoses every four years, or if cracked or damaged.

This supplementary service manual, therefore, functions as a critical resource for maintaining the Yamaha SR125 '98, ensuring its safe and efficient operation through detailed, step-by-step procedures and clear identification of maintenance intervals and specifications. Its comprehensive nature, combined with the use of illustrative symbols and clear instructions, makes it an indispensable tool for qualified mechanics.