Honda CR125 CR125R 2004-2007 Service Manual

By the time Honda closed out the CR series in 2007, the CR125R had already earned a reputation as arguably the best 125-class production motocrosser the company ever built — a title cemented by the 2003 model's substantial engine and chassis work. 2005 brought the last major mechanical revision of the model's life: an all-new engine, comprehensively reshaped and retooled with a new cylinder, piston, crankshaft, and exhaust system. Honda carried that refined engine forward unchanged through 2006 and into the CR line's final year in 2007.

Power comes from a 124.7cc liquid-cooled two-stroke single with an electronically controlled RC valve system, running an 8.6:1 compression ratio through a 54mm x 54.5mm bore and stroke, with six-petal reed induction. The third-generation twin-spar aluminum frame — the final iteration Honda developed for the CR125R — used taller swingarm pivot plates and thinner frame spars for a narrower overall cross-section, while remaining lighter than the second-generation chassis it replaced. A semi-double-cradle design routes a single large-diameter tapered downtube into two box-section rails supporting the engine, with a forged-aluminum steering head providing a compact, durable mounting point for the frame spars.

Suspension consists of an inverted Kayaba cartridge fork with separate air and oil circuits for reduced contamination and more consistent damping over a moto, paired with a Pro-Link rear shock. An optional 20-inch front wheel was available for riders seeking improved cornering traction and comfort over the standard 21-inch setup. Dunlop D742 front and D756 rear tires came standard, along with a removable rear subframe, a washable two-stage foam air filter, and a repackable silencer — all details aimed at racers doing frequent between-moto maintenance.