by Dave Willet
Former British Motocross Champion - November 2020
aking the holeshot may be a crucial part of any motocross race, but there’s far more to success on the dirt than simply getting around the first corner in the lead. Ample power that gets transferred into traction and forward thrust when you need it is essential too. As is precise cornering, braking power and suspension supple enough to smooth out the bumps but firm enough to absorb huge impacts from jumps and whoops.
All this needs to be in a nimble handling bike that allows you to pick the lines you want as the rugged track changes during the moto and nor tire you out. With the all-new 2021 Honda CRF450R, one of the key objectives was to develop a bike which makes a rider’s life easier on track. To not only get the holeshot but have consistent lap times in a lightweight machine that’s not only powerful but also controllable. Whether you are Tim Gajser taking the world championship title on the bike or an amateur racer out having fun at weekends, gate-to-flag consistency is the key to victory for riders of all levels.
To build a bike that sets new standards for production motocross machines, almost every part of the CRF450R is new for 2021. The bike looks totally different to the older model CRF450R and is 2kg lighter despite coming stock with a hydraulic clutch.
But these aesthetic changes are far more than skin deep, but are designed to improve performance. There are thinner and more compact, new-look plastics that have been designed on computer to maximise air flow. The seat is now shorter, lighter and 10mm lower at the rear, to aid the rider’s freedom of movement.
The radiator shrouds are now constructed from one piece of plastic, rather than two and include a lower vent while the radiator grills are optimised for airflow. Holding 6.3L, the titanium fuel tank has also been redesigned. Gone is the wide, twin-pipe rear end in favour of a slimmer single-exhaust style machine. The new machine is slimmer by 70mm (50mm on the left, 20mm on the exhaust side, thanks to the new single exhaust) while the tank cover has been removed.
Lightweight Renthal Fatbars® flex for optimal comfort and the top yoke features two handlebar-holder locations for moving the handlebar rearward and forward by 26mm. When the holder is turned 180°, the handlebar can be moved an additional 10mm from the base position, resulting in four unique riding positions. Even the wiring saves 100g.
Once on board, the bike feels instantly right. It only takes a few laps to understand how the bike just seems to feel more natural to ride. The whole layout makes it easy to move around on and fills a rider with confidence. The bike almost feels like it’s a part of you.
The bike feels flickable and light, thanks to the new frame and swingarm, with changes to geometry and suspension. You can feel the weight saving, and the precise handling greatly improves cornering performance.
The aluminium chassis has narrower main spars and at 8.4kg, the frame weighs 700g less than the previous design. A redesigned subframe also saves 320g at 910g. All this is not just to reduce weight but to give the chassis a new feel. Torsional rigidity of the chassis is maintained, but lateral rigidity has been reduced by 20% to increase corner speed, traction and steering accuracy. The aluminium swingarm has different flex tuned to match the frame, with narrower arms and pivot point. The Pro-Link rear suspension ratio is also revised.
Aiding the precision feel around the track are changes to the top and bottom fork yokes which are revised with more flex, for quicker steering and feel. The fully adjustable, 49mm Showa USD coil spring fork have been re-valved, the stroke lengthened by 5mm to 310mm and the axle clamps’ rigidity increased. The Showa rear shock’s main piston valving is enlarged for faster response and improved bump absorption. Its spring also uses the world’s lightest steel - to save 200g.
Rake and trail are now tighter, 27.1°/114mm (from 27.4°/116mm), and wheelbase 1mm shorter 1481mm. Ground clearance goes up 8mm to 336mm, and the bottom yoke now sits 6.1mm higher at 928mm. Dry weight is 105.8kg, a full 2kg lighter than the previous model despite the new bike coming with a hydraulic clutch.
The new CRF450R definitely turns better than the old model and that was good anyway. It’s easy to select lines and the bike loves to hold a tight line in a berm or a rut and on flat corners, it has incredible precision.
The suspension offers lots of adjustment and after my first session on the bike at the Mantova GP track in Italy, I began to dial the bike in to suit my style and speed and changed the front and rear suspension settings. On the rear I added a few more clicks to the compression to give the shock a firmer feel through the stroke that I prefer. This meant I could accelerate harder out of the turns and off the jumps. I also added more clicks on the compression and rebound on the front forks to achieve a smooth yet harder, more progressive feel though the stroke. With the top-quality Showa suspension being so easy to tune, it was quick and easy to change the feel of the bike and I instantly felt more comfortable. I could really push into the jumps and turns more with a better overall balance through the turn as it was more predictable. The new chassis, suspension and bodywork really does let you get a great feeling for what the bike is doing.
Of course, the heart of the bike is the engine and the focus for the 2021 model has been on low to mid-range. Some of the performance increase has actually been down to the new chassis layout. The air flow into the engine has been improved with a much larger airbox and a new quick-release air filter, along with a different angled fuel injector to inject fuel to the back of the butterfly valve to improve intake efficiency and cooling of the fuel charge. This combination, helped by a lighter 46mm throttle body which optimises intake efficiency and makes active use of latent heat vaporisation in the inlet ports, improves throttle response and gives more bottom to midrange power. There’s also a new centralised exhaust port, new decompressor layout and new exhaust with single muffler to boost torque and save weight.
The 449.7cc four-valve Unicam engine has a significant increase (up to 0.6kW) in peak power above 5000rp accompanied by a stronger low-rpm torque feel. The decompression system is also new to increase stall-resistance and the biggest change is to the twin exhaust ports. Like the CBR1000RR-R Fireblade, their exit is oval rather than round for improved efficiency.
The magnesium cylinder-head cover has been redesigned with thinner material and the fuel pump made smaller, a hydraulic clutch improves both control and feel at the and clutch capacity has been increased with an extra plate and friction spring to maximise power transmission and durability. The clutch action is excellent with instant engagement, and the light feel of the clutch also made the bike feel lighter overall.
The change to the power of the bike is instantly noticeable. The low to mid-range grunt has been beefed up which gives you a wide spread of usable power. I didn’t feel a hit in the range at all - it was all so smooth and progressive. The power spread was huge even in second gear, the over-rev was very good too.
Like the suspension, it’s very easy to dial in the power delivery for your own skill, preference or track conditions. A gear position sensor allows the use of three specific ignition maps for 1st and 2nd, 3rd and 4th, and 5th.
I tested different map options and there’s almost too much adjustability! A wise rider will spend time testing the settings as the bike’s power can be fine-tuned in lots of different ways.
I worked out that with all the ignition and traction control maps available you could actually change the engine characteristics 12 ways. You can feel a difference between all the maps.
Even in settings that weren’t to my liking, the bike didn’t stall or bog on me all day. And once you get it right, it’s a truly awesome machine and is so easy to go fast one
And luckily, it’s also easy to stop. Up front, the twin-piston brake caliper has 30 and 27mm diameter pistons and 260mm wave-pattern disc; along with low-expansion hose for a strong feel and consistent staying power. With Dunlop’s MX33F/MX33 soft-terrain tyres fitted as standard equipment, there was ample grip in acceleration and braking which just gives you confidence. Its confidence to go faster, for longer, that makes a such a big difference on the new 2021 Honda CRF450R. Honda has got it very right with this new machine. Not only for professional riders at the top of the sport, but for hobbyist riders and serious racer no matter how fast they are. It’s easier than ever to ride this bike fast and it doesn’t tire you out. From gate drop to chequered flag, the new 2021 CRF450R delivers a stunning ride.