2002 Yamaha YZ125P Owner's Service Manual (YU-1135-A)

• Official 255-page Yamaha publication (YU-1135-A, 2002 edition) covering the 5NY-series competition motorcycles
• Applies to the 2002 Yamaha YZ125P, YZ125LC, and YZ125(P) models
• Includes primary market variants for the USA, Europe, CDN, AUS, NZ, and ZA
• Features technical specification tables, exploded-view diagrams, torque settings, cable routing diagrams, and maintenance schedules

Inside the Manual

This OEM publication breaks down the 5NY-series into seven core sections. It delivers the exact factory specifications necessary for general maintenance, engine overhaul, chassis upkeep, and electrical diagnostics. The manual lays out the baseline settings and performance tuning configurations required for these race-tuned machines. Early chapters cover vehicle identification and strict safety protocols for handling competition motocross units. From there, it moves straight into routine upkeep. Maintenance intervals for engine components, cooling systems, brake hydraulics, and suspension geometry are clearly mapped out. Working on high-performance two-strokes requires precision. Neglecting factory tolerances or improper handling of high-pressure components can lead to catastrophic failure. Always verify your tools and technical capability before initiating heavy teardowns.

Specification Highlights

Precision matters when rebuilding a race engine. This document details the exact factory measurements required for the job. Standard cylinder bore tolerance sits between 54.000 and 54.014 mm, with spark plug gaps set at 0.5 to 0.6 mm. You will find complete tables for every critical fastener. Cylinder head nuts demand 28 Nm (20 ft-lb) of torque. The front axle nut requires a solid 125 Nm (90 ft-lb). Fluid capacities are explicitly listed to prevent overfilling and blown seals, pinning the transmission oil volume at 0.65 liters and total coolant capacity at 0.95 liters.