CRF300L

Engine

• Larger capacity 286cc engine puts out an extra 1.9kW and 4Nm
• Revised gearbox ratios for both acceleration and cruising
• Assist/slipper clutch with 20% lighter lever load

An extra 14% cubic capacity for the single-cylinder, liquid-cooled DOHC engine – from 250cc to 286cc – is acquired by a 63mm stroke, as opposed to 55mm. Bore remains 76mm, as does compression ratio of 10.7:1. Peak power of 20.1kW arrives @ 8,500rpm, peak torque of 26.6Nm @ 6,500rpm (up from 18.2kW @ 8.500rpm/22.6Nm @ 6,750rpm). The full dyno graph curves tells the full story beyond the peak power and torque uplift: the new engine is considerably stronger, everywhere, from 2,000rpm up.

To match the engine’s heavier punch and to smarten pick-up and acceleration, gear ratios 1-5 are shorter, while 6^th gear is taller for more relaxed highway cruising. Addition of an assist/slipper clutch reduces lever load by 20% and manages rear wheel ‘hop’ on rapid downshifts – great for control, on or off-road. On the highway, top speed goes from 129km/h to 132km/h.

Revised timing of the intake cam specifically boosts low- to mid-range response – the rpm range most used around town or off-road – and works with redesigned air filter, exhaust downpipe (660g lighter than the previous design), muffler and ignition timing. An iridium spark plug, along with precise metering of fuel from the PGM-FI injection system, further enhances combustion efficiency and improves environmental credentials.

The engine uses an offset cylinder, reducing internal frictional losses, while the piston itself incorporates a special surface material, plus molybdenum coating. The oil pump features an internal relief structure that prevents aeration of relieved oil. The crank journal employs a half-split, press-fit metal bearing while the crank bearing uses a cast-iron bush. A primary balance shaft further reduces vibration.

The cooling system uses a 12.7kW heat-release radiator, sited on the left of the bike, protected with a polypropylene grill baffled to improve airflow. A thin guide-ring cooling fan is used to maintain even temperatures at low speeds, either in congested traffic or tricky off-road situations.

The CRF300L engine is fully EURO5 compliant.

In the process of its transformation the CBR650R has become, deliberately, a rare breed: a sports bike that provides similar pleasure, enjoyment and adrenaline to an RR machine, yet with enough practicality – and sensible running costs – to make it a viable option as day-to-day transport in addition to weekend fun.

Chassis

A total of 4kg has been saved overall from the CRF300L’s chassis, with wet weight of 142kg. The steel semi-double cradle frame is completely new and contributes 2.15kg to the weight loss. Just as importantly, to promote handling feel and connection to front/rear traction, its flexibility balance has been tuned with 25% less lateral rigidity.

This has been achieved with decreased width (-30mm) for the main down tube and smaller, 25.4mm diameter lower down tubes (from 28.6mm) plus a 20mm decrease in width across the central bracing tube.

To match, the one-piece cast aluminium swingarm is not only 550g lighter, it features a 23% reduction in lateral rigidity. It’s also 15mm narrower just behind the pivot point and smooth, cross-sectional shaping is used to create uniform deflection. Extruded aluminium is used for the chain adjustment collar. The steel bottom yoke of the previous design has been changed for aluminium; this shaves 730g from an area high relative to the centre of gravity for faster steering response.

The 43mm Showa inverted fork gains 10mm of stroke to 260mm, with spring weight and damping settings revised for precise control over a wide range of terrain and speeds. Pro-Link rear suspension now features a 260mm axle stroke, from 240mm; the Showa shock absorber is a single tube design.

Ground clearance has been increased, from 255 to 285mm and the frame and engine sit 20mm higher, thanks to revisions to the lower frame, engine crankcases and oil drain plug. Rake and trail are now set at 27.5°/109mm (from 27.6°/113mm) with 10mm longer wheelbase of 1455mm. Turning radius is 2.3m.

The front brake uses a single 256mm disc gripped by a two-piston caliper, the rear a 220mm disc and single-piston caliper; in common with the CRF competition machines the rear master cylinder is now a lightweight, integrated design. The discs feature a wave design – also taken directly from the CRF250R/CRF450R – with exceptional self-cleaning abilities in adverse conditions. 2-channel ABS is standard.

Lightweight aluminium rims further reduce unsprung mass; for 2021 the Alumite surface has been polished to a gloss finish. Block pattern enduro-style tyres (front, 80/100-21 51P and rear 120/80-18 62P) provide traction in a wide range of riding situations.

The 21-inch front wheel and 18-inch rear increase stability on rough terrain and allow the fitment of more off-road specific tyres if required. Application of a machined rear sprocket and M8 bolts (instead of M10) plus hollow rear axle saves 240g and 160g respectively.

Styling & equipment

• Lighter, slimmer bodywork inspired by competition CRF machines
• Revised riding position promotes natural control
• Positive LCD display even easier to read

Drawing yet more inspiration from the racing CRFs, the CRF300L wears a crisp set of new bodywork and graphics. The 7.8L fuel tank is 190g lighter and slimmer than before to aid movement forward, and matched by a narrower forward seat section. The rear number plate bracket is also much reduced, for a 300g saving, while the aggressively shaped front mudguard is also lighter.

To foster easy, light control, the riding position has been subtly altered: the handlebars are have been pulled back slightly, while the foot rests have been lowered and also moved back, to make gear changes in heavy off-road boots easier. Seat height is increased 5mm, to 880mm, for a naturally upright ‘rider triangle’. The side stand, too has been redesigned with a 10% larger area for its (new) folding footplate.

A redesigned, 70g lighter LCD display features large black digits on a crisp white display, for instant readability. The speedo numbers are also 6mm larger, at 23mm. Information includes gear position indicator, fuel mileage and consumption, average speed, stopwatch and rev-counter.