Yamaha WR 450F

Yamaha’s range-topping enduro machine, the WR450F, gets a significant makeover for 2012, including a revised engine, uprated frame, new bodywork plus a raft of detail changes.

The single-cylinder, 449cc, five-valve powertrain gets a reworked fuel-injection system intended to give ’more responsive and adaptable performance’, while a new ‘bilateral’ aluminium beam frame is almost 250-size in a bid to give quicker steering and sharper handling.

To match the frame, new slimline bodywork is also claimed to be to 250-class dimensions while the overall look is refreshed with new black Excel wheel rims, Pro-Taper bars and a new headlight cowl.

A ‘Competition Kit’ will also be available for riders using the bike in closed course enduros. It comprises race-spec exhaust, including silencer and tail pipe, 13/50 sprocket set and other items.

Following its successful introduction alongside its 2011 YZ450F motocrosser, for 2012 Yamaha is also offering WR450F riders the option of buying its ‘Power Tuner’, which enables bikes fitted with the competition kit to adjust the engine mapping to suit conditions.

The challenge was how to improve on an already peerless motorcycle. But the team stepped up to the mark and delivered a motorcycle that the whole nation has been hanging out for... a bike that retains the hallmark features of reliability with the versatility to win at the highest level while still providing an easy-to-ride trail weapon.

The target customer is the fast trail rider and expert enduro rider. And the goal is to improve handling in the tight stuff while striving for even more linear and manageable power.

The handling goal has been achieved with the development of a new aluminium bilateral beam frame that is very similar to the much hailed 2012 YZ250F frame that offers scalpel sharp steering and rail-like turns. The WRF version of this frame has enduro specific dimensions and rigidity balance which includes different engine mounts and a new mounting position for the subframe, which itself is comprised of a new aluminium alloy.

The result is blend of strength and rigidity in a compact machine that sets new standards in enduro handling. The new WR450F provides a light feel, amazing front wheel grip, superb rear wheel traction and improved steering designed to light up the singletrack. In short, the next step in off road chassis performance.

To complement the new frame, new YZ inspired twin chamber suspension is fitted front and rear to soak up the harsh terrain that fast trail and competition enduro riders encounter. Once again, the suspension is specially endurotuned by combining the ability to absorb big hits with a softer initial travel to tackle tight turns.

And in order to offer stable engine performance irrespective of fluctuations in air temperature or altitude, a fuel injection system has been adopted. This can easily be adjusted with a hand held, portable Power Tuner device, the same unit that has proven so popular with YZ450F owners.

Review

Yamaha certainly pushed me out of my comfort zone last week at the launch of their new WR450F in spectacular mountainous territory around Dorrigo (NSW). Enduro bike tour company, Coffs Harbour Detour, were tasked with setting the course, and it was a doozy.

A lot of the terrain is regularly covered with their tour groups, but due to the level of riders on our launch quite a few ‘special test’ style sections were added in to satisfy the Pro level riders amongst us. Riders present included; Finke Desert Race winners, a NZ Hare Scrambles Champ who surely is the result of some Kiwi microbiology experiment fusing mountain goat DNA with that of a human, and dirtbike legend Stephen Gall who seemingly floats on a higher plane above the machine and controls it by telepathy rather than human movements; demonstrating the effortless grace and perfect technique that enabled him to rule Australian motocross tracks for so long, and coach virtually every top Australian rider in recent times.

I was more than a little out of place amongst such greatness. Devoid of fitness or talent I nonetheless muddled through and ‘eventually’ conquered every obstacle in my path, largely thanks to the brilliance of the new Yamaha.

After two days of riding together I questioned Boris and Luke from Coffs Harbour Detour Tours about the general level of skill among their regular clientele in comparison to mine. They noted my level was about the same as their average customer, who generally would not be taken on a few of the more testing tracks we traversed, but is exactly the target market for the new WR450F. Thus my feedback is likely to be more relevant with what those at that average level of enduro bike experience. We may stick mcnews.com.au resident fast gun Mark Willis on a WR for more pro level feedback at a later date.

Experts chose a hard hitting map for much of the route, (a level of tune I also sampled for the grass track loop and much of the first day’s challenges) I, wisely opted for a softer map for the rigours of day two due to the slipperier nature of the surfaces and the more extreme ascent and descent gradients encountered. Mapping changes done in a matter of seconds via a hand-held tuning unit renders old style clip, needle and jet fettling to the dark ages. Good riddance I say.

There is nothing quite as exhilarating as a finely tuned flat-slide carburettor when on the gas, but in every throttle opening, except wide open, the latest electronic trickery wins hands down. On the WR450F a manual adjustment is still provided for the idle - which I adjusted a couple of times before finding the sweet spot as the engine loosened up - and like the mapping, is easily adjustable for rider preference and the conditions.

The fuel injection system provides crisp fuelling with a smooth pick-up from closed throttle. This particular Yamaha system, first introduced on the YZ450F last year before graduating to the WR450F for 2012, is absolutely ace - I couldn’t fault it. Smooth off the bottom to help find the elusive last skerrick of traction where there is none, it builds into a wide torque-laden mid-range with added pep up top, and graced with a generous amount of over-rev it was simply flawless. Effortless starting is provided via button with the trusty back-up kick-starter provided should your battery go flat. The machine can also be used without a battery should you want to save weight, thanks to a larger magneto fitted to power the fuel pump and EFI system.

The first time I thought of the clutch was at the post ride debrief when filling out a questionnaire on the bike for Yamaha Japan WR450F project leader Masaki Kamimura, who also rode with us on the first day of testing. It was only then that I remembered just how faultless the take up and engagement of the clutch had been throughout the ride. The clutch allows for effortless restarts halfway up snotty hills even after looping out. The gearbox was also fuss free with engagement very positive and false neutrals rare. Likewise the braking performance was predictable with good feel at the lever.

The superb chassis was developed in conjunction with the nimble YZ250F motocross machine and is graced with vastly improved new 48mm twin-chamber forks and a well damped shock, making the new WR450F a class package.

Despite my, ahem, widening girth, the new forks worked brilliantly and shrugged off the worst of my timing mistakes over obstacles, and with the shock preload wound on to provide 90mm of sag it was easy to keep the front planted when required.

The nimble steering geometry allowed me to easily change my line of attack on rutted sections while retaining enough stability to prevent me darting all over the track as I strayed over odd shaped rocks, or slipped over gnarly tree roots that were seeking to bring me undone. Due to my well-honed sense of self-preservation and caution, deflection is one trait I can’t abide on the trail. Thankfully the WR450F was rock-solid in the stability stakes at low speeds. Over the two days, only one brief section of track saw higher speeds reached, thus I can’t make a definitive call on the stability of the WR450F at speed, but certainly encountered nothing to suggest that this might be a problem. I would expect wide-open desert racers to fit a steering damper as a matter of course.

The standard foot pegs offered great purchase for my boots and the long, slim seat worked well ergonomically. I am not a doyen of body positioning by any means, but I never felt in the least bit restricted and never heard any complaints from the more animated riders amongst us.

Shorter riders will rejoice loudly at a welcome feature of the new WR450F. Seat height has been lowered to 960mm as a consequence of Ground Clearance being reduced to 335mm. I never bottomed out either end of the machine and only once struck the lower frame rails while making a judgement error negotiating a downed tree. At a short legged 178cm, I found the reduced reach to the ground, for a quick dab of the boot to regain front traction, quite reassuring.. The reach to the bars is also 10mm shorter.

Reliability was also a high priority for Yamaha engineers. Larger radiators, wider big-end bearings to cope with the low speed chug loads made possible by EFI, a piston oil-jet sprayer to help cylinder cooling and a myriad of other changes were introduced to improve serviceability. The dry sump engine retains the five-valve layout of the previous WR450F, a top-end design with an unparalled record of reliability in recent years. This record will help endow confidence in prospective purchasers, a very important point in the world of high-performance enduro machines in regard to ongoing ownership costs and an area where Yamaha has the runs on the board.

The standard machine ships with Bridgestone Gritty rubber. Our launch bikes were fitted with a Dunlop D952 rear hoop and a Metzeler Six Days Extreme up front, a combination that worked extremely well across all surfaces encountered.

The only thing the WR450F did wrong during my time with it was to sometimes take a few stabs of the starter button to fire, and a muffler bolt worked loose on another machine. The lack of any ignition key or physical security demands that a cable lock be carried for overnight stops.

Dynamically the only slight flaw I found was that, despite the agile handling and slim profile, the WR felt a little heftier than would be preferred. While no scales were present at the launch, Yamaha staff claimed the machine is 114kg dry in enduro trim with ADR road gear removed, or 129kg with its 7.2 litre fuel cell full and all ADR accessories in place.

The modest 7.2 litre fuel cell is a restriction for many but Yamaha are only weeks away from introducing an optional larger main tank and auxiliary rear tanks for more long-distance adventures. A warning light on the instrumentation illuminates when two liters are remaining in the standard tank. Obviously standard range is largely decided by your wrist, and we didn’t run the machines dry, but guesstimates are: an average 100km range; reducing to 80km for fast aggressive riding; or extending perhaps as far as 120km in more moderate use.

Clearly, the WR450F is no lightweight motocross machine, nor is it designed to be, but for most weekend warriors and enduro riders the WR will pose no problems and will be forgiven if the new WR450F lives up to the rugged reputation earned by its recent predecessors.

The expected reliability along with the tractable engine and excellent suspension make the $12,999 WR450F my preferred option in the big-bore enduro market. Incorporated in that price is a competition kit valued at $650 inclusive of a new front master cylinder, braided brake line, handguards, GYTR muffler tip, LED tail light and plate holder, brake snake, 13/50 sprocket set and wiring for the optional ($399) power tuner.

- Pictorial - Yamaha WR450F Image Gallery

+ Positives
- Smooth tractable engine
- Easy EFI tuning
- Throttle response
- Excellent suspension

- Negatives
- A little heavier than ideal
- No security
- Three month parts only warranty par for the course in this segment but still not generous enough

Source mcnews.com.au