Yamaha WR450F

Who would have thought it would all turn to poo? Literally. In offering me her assistance for a photoshoot at the recent launch of its 2003 Yamaha WR enduro range, Yamaha Australia Marketing Assistant and fellow Oz Safari competitor Cheryl Muldoon had unwittingly sealed her unfortunate and somewhat smelly fate.

The plan was to wheelie side by side while lensman Barry Ashenhurst snapped away and, for the first few passes, that's just what happened.

But, with Cheryl being new-ish to wheelstands, and keen to impress with a good showing, we were on thin ice. Sure enough, on about the fifth run it all went pear-shaped.

I was positioned slightly behind Cheryl, shortly after we had both bumped our respective mounts on to the back wheel (me on the 250, Cheryl on the 450), when the sheer height of Cheryl's front wheel snagged my attention. The thing was impressively vertical. Too much so.

Before you could say 'rear brake', Cheryl was frantically paddling her booted feet behind the hither-to pristine WR450F, before giving in to the inevitable and diving to the ground behind a gracefully looping WR.

Unfortunately for 'Chez of the Desert', cow-pats were a major feature of the terrain in which we were sampling Yamaha's latest. As she rolled through a large, mildly fresh dung-pile, a cloud of some nondescript insects erupted skywards, which only served to make me laugh even harder. Needless to say, verybody gave Cheryl a wide berth for the rest of the day...

STAND AND DELIVER
"It's not just about the electric leg", so says the Yamaha press kit, in reference to the myriad of changes wrought on its WR enduro weapons for 2003. And that's especially true of the 450F.

Even so, the 'magic button' is a major feature of the comprehensively revamped model. That and the capacity increase.

Since the original WR400F knocked everybody's socks off back in 1998, the model has been an overwhelming success. The WR single-handedly set in motion a resurgence in four-stroke dirtbike popularity. It did everything a two-stroke could, but with many advantages in reliability and rideability.

This is reflected in the sales arena. For example, in 2001 (the same year the capacity bumped up to the 426cc of the YZ motocrosser it's based on), 1317 WR426Fs were registered in Australia, topping the rego list overall. Its closest opposition was, believe it or not, the WR250F with 893 units registered. And it's a similar story for 2002, with both models heading the Aussie sales charts as at the end of September (final 2002 figures have yet to be collated).

Yamaha is well aware of the importance of its flagship enduro model sales-wise, and in fact the Australian-market WR450F was developed here, by Australian riders, as well as in Japan. Yamaha wants the WR to maintain its top selling reputation, and the addition of the electric start can only help.

WEIGHTY ISSUE
But the WR450F powerplant isn't simply a stroked WR426F engine with an electric starter bolted on. It's completely re-worked, the aim being to not only accommodate the starter motor, but to also make the bike more manageable to ride with a more linear and controllable power delivery.

The 426 can be a bit intimidating, especially for the average punter, as its power delivery is almost two-stroke like - the engine comes on strong near the top of the rev range. The 450 is much more linear and tractable in comparison, but still with plenty of punch and a stratospheric rev ceiling.

The Aussie launch of both models began in Thredbo (NSW), nestled among the spectacular Snowy Mountains, and our day's ride began with a short squirt along the bitumen of The Alpine Way, en route to our off road destination.

While bitumen is hardly this bike's domain on brand new Michelin Enduro Competition road-legal knobbies, the run did highlight just how smooth the new powerplant is - especially considering the bikes had less than 12km on the odometer.

The weight shaved off the engine internals is also apparent as the throttle response is remarkably crisp, but it's uncanny how few vibes there are from the liquid-cooled single. The days of fat, bum-numbing four-banger vibrations are apparently numbered...

FARM HANDS
The venue for our sampling was picturesque Tom Groggin Station, a private property owned by a generous bike nut who was quite happy to allow a reckless mob of motorcycle journos and Yamaha staff the run of the place.

It is an ideal place for testing a dirtbike, with vast green paddocks (littered with the afore-mentioned cow pats) plus ready access to numerous trails around, up and over the Snowies. There was even a creek in which to rinse off the dust. Perfect.

It wasn't long before a small 2nd/3rd gear motocross track was carved out of Tom Groggin's pristine paddocks, where the new engine's manners made themselves known.

Short shifting through the slick changing five-speed 'box to make the most of the new engine's prodigious mid-range grunt, the bike responded happily. But the engine's lighter internals and five-valve cylinder-head (containing shorter titanium valves) are just as happy in the upper reaches of the rev range. The extra over-rev (via a new CDI) is noticeable here.

The extra torque results in more tractability and less energy sapping wheelspin, without losing out on sheer top-end speed. Versatility plus!

The journos present were of varying abilities, ranging from Australian-level enduro guns to dirtbike first timers, but everybody heaped praise on the engine.

Smooth, grunty, predictable and fast - the WR450F has something for everybody.

THE BUTTON
The electric start works a treat, comprehensively rectifying the starting foibles that plagued the 426 and 400 - particularly when hot. Now that Yamaha has caught up with the trend set by the European opposition a number of years ago, the WR should become an even more formidable presence in the sales charts.

Ironically, the new engine now comes equipped with a handlebar-mounted hot start lever and an auto-decompression arrangement, in place of the tricky to operate hot-start button and manual de-compression lever. Kickstarting the bike hot or cold is a breeze - but completely unnecessary. Just push the button and go!

Yamaha claims a dry weight for the new bike of 112.5kg, exactly the same as the 426, despite the addition of the electric start hardware. This is a result of the weight saving measures undertaken in the engine department. Impressive.

BUT THAT'S NOT ALL
The new engine and electric start are in fact so impressive, that they almost overshadow the heavily re-worked chassis. Almost, but not quite.

Yamaha claims the WR450F utilises the first super high-tensile steel frame in motorcycledom. Fair enough. The benefits are reputed to be its light weight and zero lateral movement, whilst retaining some compliancy for rider feel.

I'm not going to attempt to convince anybody that I can feel the difference after riding the bike in isolation, but the chassis is very, very good.

What I am sure of though is the much improved ergonomics and styling. The bike is visually slimmer, thanks to a similar design to its YZ450 motocrosser stablemate. The re-shaped 10-litre tank, flatter seat and new side panels provide much more manouverabilty around the bike than the 426 and especially 400 - a feature the European enduro bikes have until now executed much better. The re-design also neatly accommodates the necessary battery.

I could get my weight much further forward than on the previous model. The 'bars are a bit low for me when I'm standing, but they are strong enough to withstand reasonable-sized oopsies. Even on the bitumen as one unlucky journo discovered...

Also improved is the access to the air filter, which is now a tool-free affair.

The new seat's comfort, too, is worthy of a mention. It is of almost perfect density. Firm enough to allow easy movement fore and aft, yet forgiving enough to be comfortable all day. It looks good too in its black and blue colour scheme. One of the better dirtbike seats around.

PLUSHNESS PREVAILS
The 46mm Kayaba forks and rear shock are plush-o-rama, and boast enough adjustment to truly bamboozle those with the mechanical aptitude of a three-toe sloth.

The shock features low and high-speed compression damping adjustment, as well as rebound and spring preload. The fork 'makes do' with compression and rebound only.

Just bouncing the rear suspension by hand revealed what seems to be very light damping, but reaching the end of the shock's 315mm stroke actually takes some effort. It absorbs big hits and small corrugations beautifully, as does the front fork, without punishing the pilot.

If the bike was my own however, I'd swap the standard rear spring for something one rate heavier, as my 88kg was a bit much for it at times. I reckon that's all the modifying the suspension needs, as the damping is pretty good out of the box. On the launch I slowed down the rebound a tad and added a bit of compression to the rear, and that was it.

The revised brakes are also excellent. Suffice it to say that they do their job very well.

MARKET LEADER?
By mid afternoon, all the bikes had loosened up nicely thanks to the extra kilometres, and they carried all concerned to the heights of Mt Pindbar with ease.

Mt Pindbar is the highest place you can legally ride a dirtbike in Australia, and while the air was getting pretty thin, the WR450F still pulled hard and strong the entire way, with standard jetting in the modified for 2003 carb.

As we sat around at the end of the day, all were in agreeance that the 450 is substantially improved over the 426, and that's due to much more than the magic button. The press kit's claim appears to be correct.

Yamaha couldn't confirm a price for the 450 as AMCN was going to print, but it will be slightly more than the $10,899 WR426F it replaces. Expect it to be available in early February, where it will go up against the likes of KTM's 450EXC ($11,990) and Husaberg's FE400 ($12,295).

Yamaha has taken its best selling WR426F and made it substantially better in almost every area to produce the WR450F. It offers something for professional racers and weekend warriors alike, and looks set to continue the four-stroke domination of the dirtbike market.

Will it remain a best seller? We'll have to wait and see, but I reckon it's a good bet it will.