1985-1986 Honda TRX125 Fourtrax Service Manual • P/N 61800-958-010, published 1985

Honda TRX125 Fourtrax (1985–1986) Technical Overview

• Covers both 1985 and After 1985 design variants of the Honda TRX125 Fourtrax.
• Official Honda shop manual (Form 61800-958-010), featuring 93 pages of technical specifications, torque values, and system diagrams.
• Available as an instant download immediately after checkout.
• Printable format allows you to bring specific pages directly to the shop floor without ruining a physical book.
• Serves as the primary reference for the 124cc air-cooled single-cylinder platform.

Technical Documentation and System Walkthrough

If you are rebuilding or maintaining the Fourtrax 125 platform, this manual provides a complete breakdown of the machine. The document separates the ATV into logical systems. You get a clear look at maintenance schedules, lubrication flow, and cable routing. Need to pull the motor? Dedicated chapters cover engine removal, cylinder head teardown, and valve maintenance. The fuel system section is particularly useful for fine-tuning, detailing carburetor adjustments, pilot screw settings, and high-altitude configurations specific to this series.

Specification and Reference Data

Beyond general procedures, this file delivers the hard numbers required for a proper build. Standard cylinder compression is rated at 12.5 ± 1.5 kg/cm². Intake and exhaust valve clearance should be set to 0.07 mm on a cold engine. When assembling the bottom end, note the crankcase holds 1.2 liters of oil after disassembly, which drops to 1.0 liter for standard drain intervals. The text also lists critical fastener specs, including the 20–22 Nm torque requirement for cylinder head nuts. Always ensure your workspace is secure and follow standard shop safety practices before starting any heavy disassembly on this equipment.