1985-1988 Yamaha Badger 80 / YFM80 Service Manual
Yamaha Models Covered & Key Technical Specifications
Models: Yamaha Badger 80, YFM80
Model Years: 1985–1988
Serial Numbers: JYA55X00*FC000101, 55X-000101
Technical Data:
- Engine type: 4-stroke
- Idle speed: 1,800 ± 50 r/min
- Compression pressure (standard): 1,177 kPa (12 kg/cm², 171 psi)
- Intake valve clearance (cold): 0.05–0.10 mm (0.002–0.004 in)
- Exhaust valve clearance (cold): 0.075–0.125 mm (0.003–0.005 in)
- Engine oil capacity: 0.85 L (0.75 Imp qt, 0.88 US qt)
- Tire pressure (standard): 19.6 kPa (0.2 kg/cm², 2.8 psi)
- Main jet: #80
- Main fuse: 10A
Yamaha Manual Features & Content Preview
- Covers the 1985–1988 Yamaha Badger 80 (YFM80), including technical specifications for the 55X-series engine and chassis components
- Official Yamaha service publication (P/N 55X-000101) detailing all engine, electrical, and carburetor parameters needed for a comprehensive repair
- Features 147 exploded-view diagrams that clarify component assembly, lubrication points, and internal engine tolerances
- Provides 173 pages of specialized tune-up requirements, internal clearances, torque values, and chassis inspection intervals for the 4-stroke architecture
What the Manual Documents
Professionals and experienced mechanics rely on precise factory data to maintain these classic ATVs. This reference details every essential system for the YFM80. It starts with machine identification and special service tools, then transitions into periodic maintenance and lubrication cycles. Readers will find a thorough overview of the engine overhaul process. This covers crankcase, cylinder head, and transmission disassembly. Additional chapters break down the carburetor and chassis systems, focusing on wheel service, brake adjustments, and steering system inspections. Detailed electrical component diagnostics provide the exact specifications required to plan an accurate repair.
Specification Highlights
Technical tables provide precise tolerance charts for engine parts, such as piston clearance and valve seat widths. Critical engine data is clearly laid out. For instance, intake valve clearance sits at 0.05–0.10 mm. The factory compression pressure is documented at 1,177 kPa at sea level. Fuel system tuning relies on the main jet, which is factory specified at #80. Always refer to the original factory documentation and rely on qualified technical expertise before starting any hands-on work, as proper safety procedures are essential when handling mechanical systems. This complete reference directly targets the 55X-series production run, ensuring mechanics have the exact fuel-system and electrical specifications for this model.
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