Kymco Maxxer Mongoose 250, Mongoose 300, MXER 250R ATV Repair Manual (P/N 4122-ATV250-S00)

This official 100-page Kymco OEM publication (P/N 4122-ATV250-S00, June 2005) delivers factory-grade technical data for the 2005 Maxxer and Mongoose ATVs. Built for professional technicians and experienced DIYers, it provides the essential diagnostic references needed for the 4122-ATV250-S00 build.

• Covers the 2005 Kymco Maxxer and Mongoose 250 and 300 models, including the MXER 250R variant.
• Features highly detailed specifications for the 249 cc and 270 cc liquid-cooled powerplants.
• Contains 20 distinct system chapters documenting engine, chassis, electrical, and fuel-delivery metrics.
• Includes over 100 exploded-view component illustrations, precise torque sequence tables, and complete electrical harness routing schematics.
• Provides the primary technical baseline for the original 250 and 300 engine series, detailing all cooling system and frame maintenance parameters.

Component and System Documentation

The factory documentation breaks down the ATV's architecture across 20 focused chapters. You get a clear look at everything from frame cover removal to exhaust muffler servicing. It maps out strict periodic inspection requirements. This includes factory benchmarks for valve clearance adjustments, air cleaner maintenance, and drive chain slack settings. Moving deeper into the powertrain, the manual covers the cylinder head, camshaft holder, piston, and lubrication systems in heavy detail. For electrical troubleshooting, you will find comprehensive schematics and dedicated starter system diagnostic charts for both engine displacements.

Specification Highlights and Technical Data

Accurate reference values are the backbone of any serious workshop. This document lays out the exact baseline numbers required to evaluate engine and chassis health. For example, standard cylinder compression on both the 250 and 300 models is rated at 16 kg/cm² (1600 kPa, 227 psi). Cold engine valve clearance needs to hit exactly 0.1 mm (0.004 in) for both intake and exhaust. You also get precise fluid volumes, such as the 300 cc gear oil capacity for a standard change, alongside indexed transmission and cooling system capacities. Please note that while these factory specifications provide an essential diagnostic baseline, a certified technician should always oversee or perform actual mechanical service on these vehicles to ensure operational safety.