| Component | Specification |
|---|---|
| Engine Oil | Pro Honda GN4 SAE 10W-30 (JASO MA) (0.98 L) |
| Tires (Front/Rear) | F: 90/90-21 54M / R: 120/90-18 65M |
| Tire Pressure | F: 1.0 bar (15 psi) / R: 1.0 bar (15 psi) |
| Battery | HY85S |
| Spark Plug | NGK SILMAR9A9S |
The 2017 debut of the Honda CRF 450 RX marked a historic pivot for the manufacturer, as it was the first time Honda offered a dedicated closed-course cross-country racer built directly upon the flagship CRF450R motocross platform. Unlike previous enduro attempts, the PE07 generation utilized the revolutionary ‘Unicam’ engine architecture combined with a specialized 18-inch rear wheel and a larger fuel tank, specifically engineered to dominate GNCC-style racing.
Engineering Analysis: The PE07 Evolution
Between 2017 and 2020, the CRF 450 RX underwent significant refinements. The heart of the machine is the 449cc liquid-cooled single-cylinder engine. In this ‘RX’ configuration, Honda engineers remapped the ECU for smoother power delivery compared to its motocross sibling, ensuring traction in technical off-road sections while maintaining the explosive top-end power required for open trails.
The chassis features a sixth-generation aluminum twin-spar frame designed for a lower center of gravity. For the RX, the Showa 49mm coil-spring fork and Pro-Link rear suspension received specific valving to handle the varied terrain of woods and desert racing.
Maintenance Guide & Technical Specifications
Lubrication System
To maintain the high-revving Unicam engine, MotoSpecsLab recommends the use of Pro Honda GN4 SAE 10W-30. This oil meets the JASO MA standard, which is critical for the integrated wet clutch system. The total capacity is 0.98 Liters. Given the high-performance nature of the PE07, oil changes should be frequent, especially under competitive racing conditions.
Ignition and Electrical
The PE07 utilizes a high-performance NGK SILMAR9A9S spark plug. This iridium-tipped plug is essential for consistent ignition timing and heat dissipation. Powering the electric start system (which became standard during this generation) is the compact HY85S battery, designed to minimize weight while providing reliable cranking amps in cold-start scenarios.
Chassis and Contact Patch
The RX distinguishes itself with an 18-inch rear wheel (120/90-18 65M) and a 21-inch front (90/90-21 54M). For optimal grip in cross-country environments, the factory recommended pressure is 1.0 bar (15 psi) for both ends, though this may be adjusted slightly based on terrain density and the use of rim locks or bib mousses.
Professional Verdict
The Honda CRF 450 RX (PE07) remains a benchmark for riders seeking motocross-level performance in an off-road package. Its reliability is rooted in adherence to strict maintenance intervals, particularly regarding its specific 10W-30 lubrication requirements and specialized spark plug. At MotoSpecsLab, we rate this machine as one of the most balanced cross-country racers of the late 2010s.