Honda hit 2016 hard with a host of suspension updates to their CRF450R while punching more power out of their CRF250R…
Based on the same machine that Alex Salvini is fighting for the Enduro 2 World Championship with, Honda’s CRF450R features notable developments for 2016. Similarly it’s smaller sibling, the CRF250R has had it’s engine fine tuned too…
2016YM HONDA CRF450R
The CRF450R receives revised 48mm KYB Pneumatic Spring Forks, with changes in dimension, outer tube rigidity and damping control, plus improved adjustment range.
Likewise the KYB rear shock features new damping rates and greater adjustability, with its Pro-Link ratio optimised.
Subtle steering geometry changes combine with the upgraded suspension performance to enhance handling, stability and usability.
Having consistently re-written the rules of front-end feel the 48MM KYB Pneumatic Spring Forks (PSF2) units have received updates to improve handling, stability and front/rear suspension balance; stroke remains the same but the forks are longer, with increased outer tube rigidity.
Both compression and rebound damping rates are firmer to maintain control towards the point of bottoming out and the adjustability is increased. The rear shock too has more rebound damping in the middle-upper range of its stroke, plus works a new Pro-Link ratio. It also has a wider choice of adjustments.
The new suspension setup also drives subtle changes to the steering geometry – collectively with the aim of improving handling, feel and usability from a rider’s perspective. Other updates include a revised footpeg design and a new chain roller, more compact in size.
The 15YM CRF450R featured improved power delivery, rear-wheel traction from low-rpm up and increased peak output thanks to an HRC-spec cylinder head, exhaust pipe/mufflers and PGM-FI Dual Fuel settings. It also gained the 3-way Engine Mode Select Button (EMSB) that offers a choice of 3 riding modes for the rider to select from the right side of the handlebar. Mode 1 delivers the standard combination of ECU maps, Mode 2 serves up silky-smooth throttle control and Mode 3 returns aggressive, all-out response and power. The engine is unchanged for 2016.
Chassis Key Features
The sixth generation 9.35kg aluminium twin-beam frame was designed from the outset around the 48mm KYB PSF2, working with the improved suspension performance (compared to steel springs) to deliver superb front tyre side-grip and turning ability.
And the PSF2s really build their advantage in directional stroke transitions from compression to rebound. To enhance both handling, suspension balance and stability they are now 5mm longer – stroke remains unchanged at 310mm – and feature increased outer tube rigidity just below the top yoke with a 54mm diameter (from 53.5mm).
Both compression and rebound damping forces have been increased for greater control under hard braking or when landing and the adjustment range increased from 4 click/rotate to 8 click/rotate. All adjusters are integrated into the Alumite fork caps, with high/low speed compression and high/low speed rebound damping separated on the left and right sides of each cap. Preload is adjusted via a Schrader air valve.
The compact KYB rear shock features increased rebound damping and slightly less compression, plus a new Pro-Link leverage ratio. Stroke is set at 133.5mm, with 315mm axle travel. The adjusters for high/low speed compression and rebound damping are concentrated above the reservoir for easy access.
The adjustment in fork length and shock linkage combine to make subtle – but important – changes to the steering geometry. Rake goes from 27.07° to 27°15', with trail up 1mm to 117mm. All-up kerb weight remains 110.6kg.
2016YM HONDA CRF250R
The CRF250R gets a substantial top-end power boost from a new HRC-developed cylinder head, piston and con-rod, with stronger bottom-end torque and no loss of mid-range performance.
Showa’s SFF-TAC-Air forks receive upgrades to reduce friction and improve response and damping; Showa rear shock has new settings to match.
Honda’s CRF250R has long been a potent weapon to take into battle thanks to its fluid power delivery and honed chassis that balances lightning-fast agility with sure-footed stability. It shares the same aluminium beam frame and mass-centralised design philosophy as the CRF450R and turns as well airborne as it does on the ground.
In 2015 the CRF250R received 49mm Showa Separate Front with Triple Air Chamber (SFF-TAC-Air) fork, to fully exploit the chassis’ ability. It also got the same Engine Mode Select Button (EMSB) as its larger-capacity sibling, giving a choice of 3 riding modes – standard, smooth or aggressive – for the rider to select from the right side of the handlebar.
For 2016 Honda has dialled in an array of upgrades to the CRF250R’s engine and suspension.
The main focus of the 2016YM CRF250R revolves around a completely revised cylinder head, piston and con-rod. And the result is power – and a good deal more of it up top, with no loss of bottom end response, throttle feel or delivery.
In fact low-rpm torque is improved, as is high-rpm over-rev. The exhaust downpipe now features a resonator chamber and the twin rear mufflers redesigned internals. The airbox has been revised to improve air flow.
Showa’s SFF-TAC-Air forks receive a host of internal changes plus an extra 5mm length in the top tubes to enhance traction, suspension reaction, rider feel and adjustability. The rear shock setting is also adjusted to match.
Other changes include a reduction in final drive chain roller diameter and improved mud-clearing ability for the footpegs.
The CRF250R’s 249cc four-valve Unicam engine retains a bore and stroke of 76.8mm x 53.8mm. Peak power is now 29.4kW @ 11,500rpm (from 28kW @ 11,000rpm) with peak torque of 27.1Nm @ 9,000rpm (from 26.5Nm @ 8,500rpm).
The new engine is smoother and stronger off the bottom, maintains its mid-range punch and as revs rise makes not only more power and torque, holds onto it at higher rpm and for noticeably longer – useful for stringing sections or corners together without changing gear.
The increase in peak power and torque – with zero sacrifice anywhere else in the rev-range – is due to extensive HRC development of the cylinder head. It starts, however with a new, lighter piston which also delivers a compression ratio of 13.8:1 (up from 13.5:1). It’s matched to a lighter con-rod, with revised shape, that contributes to the power gain.
On the intake side the airbox features an added air intake duct plus revised inner duct length and insulator. Both the intake and exhaust ports are redesigned to HRC-specification and the 25mm diameter exhaust valves are now titanium (rather than steel) matching the 30.5mm intake valves. A brand new camshaft profile operates redesigned valve lifters; both intake and exhaust valve lift has been increased. The inlet valve spring material is also new. The PGM-FI Dual Fuel Injection – with 46mm throttle body – features new settings to match the engine’s new free-flowing head.
The exhaust employs a resonator tucked away between the pipe and engine which helps improve drivability. Both mufflers use new connector tubes and inner pipe punch pattern, plus larger tail-end diameters. The left hand radiator is larger to cope with extra heat generated by the power boost and the gearbox now has a bearing-type shift drum stopper for improved feel at the gear lever. The chain roller diameter has decreased, from 38mm to 34mm.
Honda’s EMSB makes an already very usable engine even more adaptable. This is a plus for the club racer in particular; rather than set up during the week and hope for matching conditions at the weekend, the rider just has to stop with the engine at idle and press and hold the button for just under a second to select the next map in sequence.
A highly visible LED built into the lightweight button signals the map in use with a quick press and number of subsequent flashes. If a new map is selected the choice is also confirmed to the rider.
Mode 1 uses the standard combination of ignition and fuelling maps to present a balanced power and torque delivery. Mode 2 is designed for use in slippery, muddy conditions and is all about throttle control, giving easy-to-manage feel that hunts out every last scrap of traction. Mode 3 hits hard with aggressive and responsive top-end power to drive through soft sand. Mode 2 and 3 can be further tailored via the existing HRC mapping hardware and software.
The 49mm SFF-TAC-Air forks were developed specifically for the CRF250R by Showa to unlock the frame’s performance potential and save over 1kg in weight compared to conventional forks. The fully adjustable right fork leg controls both compression and rebound damping force while the left fork leg compresses air using a damper-less structure. This distribution achieves a controlled right/left balance.
Three chambers are used by the left fork leg to manage suspension reaction (or effective ‘spring’ rate). The Balance chamber operates from the off and at low speed; the Inner chamber is responsible for the mid-range stroke and the Outer Cylinder chamber is used as the forks near their bump stops.
Both fork legs employ the same stroke and internal dimensions as employed previously but have received extensive development – the two main goals to reduce friction through short strokes, improving suspension reaction speed and also to increase reaction force at mid-stroke, boosting control during pre-jumping and landing. Both rebound and compression damping characteristics have been increased to suit the new set-up.
The top tubes are 5mm longer above the top yoke, and to reduce internal friction – by approx. 25% – the construction, shape and number of inner air seals has been finely adjusted. 80kPa air pressure has been added to the Outer Cylinder chamber; previously this contained 0kPa. It also receives a dedicated air valve for adjustment. Both the Inner and Balance chambers now use 1075kPa, from 1200kPa/1125kPa. The damping adjustment range increases from 4 click/rotate to 8 click/rotate.
The compact Showa shock mounts low within the frame spars. To balance the changes up front – and maximise rear-wheel traction – it now uses a heavier spring rate in the early part of its stroke. Rebound damping remains unchanged but compression damping increases (compared to 15YM) from mid-stroke on as the piston speed rises.
Fully adjustable, the rear shock features 17-position rebound adjustment; compression damping is separated into 13-position (low-speed) and 3.5 turns (high speed). Honda’s Pro-Link rear suspension linkage operates CRF250R-specific ratios and allows 31.7cm of travel. The aluminum swingarm features deep beam height in the front and centre sections, minimising rut deflection and improving rear tyre traction on corner exit.