2014 Yamaha YZ250F

Race Bike In A Crate

Words: Broxy Pics: Four-Oh-Four

Yamaha’s next generation YZ250F is about to land in New Zealand, which DRD was invited to ride before it hits the showroom floors, so Broxy found himself in Aussie to test the all-new blue quarter-litre motocross bike… fancy a ride?

Yamaha’s latest 250F has combined the benefits of its rejuvenated big brother, with the performance of the race bikes that recently won both the NZ and Australian MX titles, morphing into what could be the ultimate production weapon.

Illuminated on the video screen in front of me was a string of wiggly lines working their way upwards, two of which were almost identical, with one lagging noticeably underneath. It was the dyno figures comparing last year’s standard power output with their hotted-up race bike and, what is quite possibly the most exciting development since they first brought out the first modern racing four stroke over a decade ago, the 2014 YZ250F…

We were in the conference room of a Toowoomba hotel, entertained by the soundtrack of talking parrots and Kookaburras laughing away on the other side of curtained windows. Until this stage, I wasn’t all that fazed at the number of the big names joining us at the tables, or the new machines dotted around us. The bikes simply looked like the 2014 YZ450F we had tested already, except for a slightly smaller engine and exhaust system. I had been very impressed with the improvements made to the bigger brother, but up ‘til seeing that slide on the video screen, there hadn’t been much of a reason for the electrons to start buzzing around in my mind until I realized just what it was they were claiming. And that was that the standard machine produces the same horsepower as their race bikes.
How is that even possible?
I didn’t have to wait long for the answer.

THE RADICALS

Their radical engine design is not backwards just to be different, like some petrol-powered emo, sitting in the gutter wearing eyeliner and a fringe covering most of their face.
No, not at all.
The airbox design is impressive, picking up loads of clean air that the engine can easily inhale. This air travels but a short distance before getting pulled directly down to the intake valve, without the final turn it would normally face inside the head itself. Picture the difficulty of Luke Skywalker firing his proton torpedos horizontally into the weak point of the Death Star, which needed to somehow turn downwards in order to reach the reactor core. While that was just Hollywood, with a little bit of the Force, science says that your fuel-rich air doesn’t like that final turn much either. And you will effectively gain horsepower by entering the cylinder ‘core’ in a much straighter fashion.

Something of a side note – albeit, an important one – is their choice of using four valves instead of the five valve heads they have stuck with since releasing the first racing four-stroke motocrosser in 2001. I am sure that this was not done without weighted consideration. But comparing the two systems on paper, the four-valve system does look more air friendly.

Coming in second, behind the advantage of a more direct air intake on this design, is how the crank is offset, just enough, that when the piston pushes down on its explosion stroke, it has less resistance and can focus on accelerating the crank. That means it has more of an angle to deal with on the way back up its stroke, but that is much less important. On the last generation of YZ450F machines, this direct approach was a problem, as it contributed to the snappy power that came on too suddenly for most riders. What I don’t know is how the Yamaha engineers kept the offset crank design for 2014 to make the most of its horsepower advantages, but managed to calm the brute out of how that power was delivered.
Whatever they did, it worked.

IN THE SADDLE

Nestled high atop what is called the Great Dividing Range, the Toowoomba Motocross Track holds a round of the Australian MX Nationals. But being 700 metres above sea level, it might not have been the best track to take us to, knowing that altitude sucks horsepower. In most cases, a standard 250 would have felt quite slow, at best. Well, they never warned us about that fact, and they didn’t need to, ‘cause the 2014 YZ250F felt fast, despite this.
That gives even more credit to their new bike.

I do wish they had a standard 2013 bike there for us to ride first, just to validate what I felt when the power gets up to around half of the max rpm, which was about the same horsepower as what the old bike used to put out as its maximum. That seems a little hard to believe but, regardless, it will make this bike easier for almost anyone to ride fast. From half rpm and upwards the power keeps getting better, reaching its peak of a claimed 5-6 horsepower after the old engine was well past its peak. And after riding it, I think you would agree.

As a four-stroke 250 should be, the power was fairly average below half rpm. This is not the kind of bike that will let you get away with laziness on the gear lever. I found myself using excessive clutch numerous times to get going out of a turn before figuring out which gear to be in. Depending on the track being ridden, I would suggest going a tooth or two bigger on the rear sprocket if you like doing most turns in third. Or doing the opposite, if you want to make second gear more useable.

This power can also be manipulated electronically, as we experimented with using the Yamaha PowerTuner. Once you have researched the figures you would like to try, it is a simple case of plugging it into the bike and using its iPod-like interface to change some numbers according to where you want to add or subtract fuel, advance or retard the ignition. It was made even more simple for us with the figures all done, all we needed to choose was ‘Racing #1, 2 or 3’. While I don’t know the exact numbers, ‘Racing #3’ did feel noticeably stronger in the lower rpm than standard, while #2 was strong down low and kept more power coming right through the top end. This impressed me, as I didn’t think it would be so easy to feel any improvement in the mapping on a 250F. Because I could feel that, there was no real need to try out the ‘Slick’ or ‘Mud’ settings for our test. Our conditions were absolutely perfect and the last thing I wanted to do was detune this little beauty.

ON TRACK

The track had held a club race just the day before, and despite being groomed and watered for us, it still had all the bumps and ruts you could hope for. Not satisfied with my first ride where the bike felt well balanced and light, I picked up my nerve and started pushing hard to see what it would do under pressure.

Braking too late and hard though one particularly nasty hole, I expected the worst. What I felt was almost an anticlimax, as it handled the hit like it was nothing extraordinary, even the second and third times. In saying that, the clicker settings on my forks were wound almost to full stiff by that point, which showed that it could do with stiffer valving for me. But that is the case on nearly all of the stock bikes that I ride, and this adjustment was made I found it very difficult to make the bike so much as flinch.

My next experiment was to relax how much I compensate for a heavy front when turning into a flat or soft corner. Sure, there was a limit to how hard the front end can be pushed, but the bike never felt twitchy or unbalanced. Out of all the things on my wish list for this bike, that one was at the very top because of what we had found in the past, so it was from here on out I could really start to enjoy myself.

So the handling is faultless and the power huge, but one question remained…
Does it feel as heavy as it looks?
You are welcome to disagree on this point but the 2014 YZ250F is so similar in appearance to the new 450F that it looks heavy, its slightly bulbous frontal region that is the airbox and radiator region adding feeling to that idea while the bike is sitting still. Well, I can tell you right now that it feels far from heavy to ride, especially whenever you need to make a sudden change of direction in any way.

You have to start believing that there must be something to this whole ‘centralised mass’ fad, when most of the latest 250 four-stroke machines start feeling like a 125 to ride. And now, with this new bike, it seems that Yamaha are leading that charge. The list describing how they achieved this is a long one, headlined by the smaller, reverse-fed engine. Moving to a wet sump design meant they did away with the external oil tank, the idler gear, scavenging rotor and oil delivery pipes. This is what the full factory race teams have been doing to their bikes for some time now, which makes it very cool to have in a standard bike.

Another copy of the race bikes is the header pipe that wraps around the head to gain the length it needed to run a muffler that now begins very close to the motor. The beauty of this is an almost completely hidden muffler, about as close to the center of mass as you are ever going to get. This did cause a problem for the designers, as the subframe needed modifying, but they were able to turn even this into something lighter and stronger, using less alloy to perform the same goal. It even meant they could incorporate a grab handle area for lifting it on and off your bike stand, but it might take a few goes to get used to its positioning, being lower and more forward than usual.

When it comes to centralised mass, the pièce de résistance is its incredibly central fuel tank, fuel pump and wiring systems. Weighing much more than the airbox that replaces it, a full tank of fuel is now less noticeable, especially when under brakes or hard turning. This is even with a larger capacity than before, holding 7seven and a half litres of fossilised fuel. While this will certainly create a problem for designers of oversized fuel tanks, it is something close to magic for the rest of us.

When a bike feels light you have two choices.
Either enjoy the ride for longer since it takes longer for that dreaded arm pump to set in.
Or, like, step up the intensity.
And seeing as I was only going to get a few hours on this awesome track, there was only one option!
The funny thing was that I wasn’t even getting that tired at the level that I thought was intense, which just made me step it up even more, being helped by the high numbers of top riders out there doing the same thing. Seeing Billy MacKenzie get flat around a technical berm as if riding on rails was pure inspiration. The same goes for the style shown on the jumps by recently crowned New Zealand Supercross MX2 champ, Jay Wilson, scrubbing and chucking the 250 around like a kid plays with a motorcycle miniature.

All of this goodness in a package that includes electronic fuel injection, yet weighs only 105kg when full of fluids. That is compared to the 2013, which was 103kg wet, but held one and a half litres less fuel that, according to my math, makes the EFI bike a mere half a kilo heavier than its predecessor. To me, that is incredible.
Also think of the added economy of EFI compared to the 39mm carb. And when you factor in that extra fuel, the bike should last a whole lot longer.
But the best part of all is what is missing: the bog on hard landings that plagued my last YZ250F.
It is gone, never to return… and good riddance, I say.

So this bike is a lot faster than its predecessor, without gaining much weight. If there are any reservations, they would be how the bike feels wider between your legs and there is still a strange sound coming from the tank area that is the induction noise of having the airbox in the front of the bike. Although, the thing is, neither of these things are as noticeable or annoying as the last YZ450F, so it shouldn’t take long before you are used to it.

The real test is going to be the comparison between this bike and other 250cc four-strokes. With horsepower above the magic 40hp mark, putting it right alongside the KX and KTM machines, its lightning quick yet stable handling, it is likely that anyone with blue blood will be back in the market once again… with others following suit soon after.
Yes, you could say that this is well overdue, but you know what they say right?
Good things come to those who wait.

2014 YAMAHA YZ250F

Team Yamaha Blue and White: $13,299
Special Edition White: $13,399

Engine Type: 249cc liquid-cooled DOHC 4-stroke; four titanium valves
Bore x Stroke: 77.0mm x 53.6mm
Compression Ratio:13.5:1
Fuel Delivery: Yamaha Fuel Injection (YFI) Keihin® 44mm

RUNNING GEAR
Transmission: Constant-mesh 5-speed; multiplate wet clutch
Front Suspension: KYB Speed-Sensitive System, inverted fork: fully adjustable, with 315mm of travel
Rear Suspension: Fully adjustable single shock with 315mm of travel
Front Brake: Hydraulic single disc brake with 250mm rotor
Rear Brake: Hydraulic single disc brake with 245mm rotor
Front Tyre: 80/100-21 Bridgestone M404-A
Rear Tyre: 100/90-19 Bridgestone M403

Dimensions
Length: 2164mm
Width: 825mm
Height: 128mm
Seat Height: 966mm
Wheelbase: 1475mm
Ground Clearance: 325mm
Fuel Capacity: 8L
Wet Weight: 104kg