2016 Yamaha YZ450F & YZ250F - FULL TEST

By TMX Archives on 2nd Sep 15

FIRST of all hats off to Yamaha for daring to be different. In an age when each and every manufacturer follows their rivals oh-so-closely in terms of machine design and spec if one sneezes they all catch a cold it is a breath of fresh air when one breaks ranks and dares to plough their own furrow.

Yamaha has had the nerve to do just that over the last couple of years with their unique reverse-cylinder design, which was pioneered on the YZ450F and then successfully transferred to the 250F.

The marque has form when it comes to innovation, of course, having persevered with the five-valve head (three inlet – two exhaust) set-up on its on-road and off-road models before eventually calling ‘time' and settling for the simpler, universally accepted four-valve set-up.

In theory the five-valve set-up should allow more revs but in practice the gain wasn't worth the extra complication or cost.

Yamaha's reverse cylinder concept is – what else – all about performance.

By placing the inlet at the front it allows the air/ fuel mix the straightest, and most efficient, possible route into the cylinder.

The switch from carburettors to ‘efi' has facilitated this change and the down-draught is assisted by tilting the cylinder rearwards on the crankcases which in turn lowers the centre of gravity.

The rear-facing exhaust throws up the problem of getting sufficient tuned length into the exhaust pipe which Yamaha has solved by curling the header right round the cylinder.

Design

An improved version for 2016 has allowed the muffler to be moved forward thus once again centralising the mass.

The pipe itself is also a technical gem with several crucial changes in diameter in order to attain maximum performance.

The five-speed, DOHC motor sits in an aluminium twin-spar frame, the chosen design of all four Japanese manufacturers and from here on in the Yam follows conventional design and utilises tried and tested components.

For 2016 Yamaha has concentrated on refining its concept with a stiffer chassis, 5mm lower footpegs and probably the most important change, a vital tweak in the steering geometry achieved through new triple clamps.

The motor has been treated to new cams, aimed at boosting low to mid-range power, the big thing in 2016 in the 450 stakes.

The launch control system (LCS) has also been revisited and the ECU ensures you have the best chance of the holeshot, especially on hardpack where too much horsepower can result in excessive wheelspin.

Meanwhile the 250F has been treated to a redesigned, flat-top piston which also benefits from improved lubrication and cooling, the combined effect resulting in more consistent power output.

Both models sport new, softer, suspension settings and both benefit from a feisty new 270mm front disc.

Oh yes – they're blue!

That's the brief history and update over with but what you really want to know is how it goes on the track...

WHEN TMX's regular MX test pilot Martin Craven managed to miss his flight – don't ask! – to the 2016 YZ-F launch in France it left us with a bit of a problem. Fortunately Dirt Bike Rider's tester RYAN HOUGHTON was on hand to spin some laps on the new bikes for us and share his thoughts on Yamaha's dynamic duo...

Over to Ryan...

Some of you will know that I've raced Yamahas for the past three seasons, so I should be able to give you a fair explanation of what's good and what's not with the new blue machines.

After listening to Eric Eggens (former GP winner and now Yamaha Motor Europe Motocross racing manager) e xplain all the changes Yamaha intended to make with its new bikes we got to have a look at them – and I have to say that they appear to be pretty smart in stock form.

For the 2016 450F offering Yamaha's technical team wanted to make four major improvements and on the whole they've pretty much cleared the faults I experience with my 2015 bike.

I was happy to hear Eggens talk about how hard Yamaha has worked to improve the 2015 model because I've spent a long time and a fair bit of money trying to overcome niggly problems.

Power

And the 2016 YZ450F comes in bang on the money.

This new 450F is way better in standard form than my 2015 model. Yamaha has changed the standard ECU mapping, managing to keeping the raw power but making it more controllable.

This takes away the snappy aggressive feel of the 2015 model which in truth was a bit of an animal. The bike and power characteristics will definitely be more manageable in motos because there's less to worry about.

For example when exiting corners you can hit the gas harder than before without the bike getting out of control. This standard map which Yamaha now issue you with straight out of the crate is what I've taken months to find on my race bike so that can only be a plus.

I also enjoyed the 2016 refinements that had been made to the gear mechanism and the clutch. Shifting gear felt much lighter on the clutch lever while the shift lever itself had a smooth and positive action.

To me the gearing refinements and the change in power characteristics will mean that average and pro riders alike will get an easier ride next season.

Ergonomically Yamaha has lowered the footpegs by 5mm on the 2016 model to improve the package's centre of gravity.

Now I'm no scientist but I am a big lump at 6ft 3in and 13-and-a-half stone so anything that can lower my centre of gravity is mega.

In reality it was very noticeable that I was able to change direction quicker allowing me to switch lines more easily, saving energy in the long run.

Another big improvement is front end feel on the 2016 edition.

I always felt the 2015 bike was a little vague and it meant that the bike was getting away from you all the time. Yamaha have countered this by moving the fork offset from 23mm to 25mm.

This 2mm change gave me so much more confidence on corner entry and alongside that 5mm drop in footpeg position the handling has been vastly improved.

Confidence is such a big thing when roaring a big 450 into corners and now you can trust the bike to do what you want it to do.

I was really quite impressed that I was finally able to turn the bike using the front wheel.

The front forks felt a tad on the soft side for me but unless you're a real big fella or really push the front hard then the forks should be fine in standard spec.

I was impressed with the rear shock though, because it feels quite soft which makes the bike squat and gain loads of traction – that must be a good thing when your aim is to enjoy your racing but still make it to work on Monday morning.

Being flung down the track thanks to a dodgy rear shock is no fun.

Yamaha has upped the front disc size from 250mm to 270mm, which is a big deal. I run an oversize disc on my 2015 bike and it is a handy piece of kit. It probably comes down to confidence and if you believe in that front disc then your corner entry speed is more likely to improve.

Overall this bike is the nuts, I really liked it.

It would certainly be money well spent and even if you don't believe me give it a test – you might surprise yourself because Yamaha has definitely gone to town on its MX1 class offering.

Yamaha YZ250F

THE new 250F hasn't had a huge amount of changes for 2016 but wow, it is fun!

Yamaha set out with a plan to enhance the engine usability while improving braking power and controllability.

And t hey have achieved that by the bucket load.

In essence the 250F has taken the same refinements as its big brother, like the new 270mm front brake disc and a new clutch boss with increased surface flatness for precise and accurate operation.

The transmission also gets a stronger spring on the shift stopper ‘giving a smoother and more accurate shifting under pressure'.

The piston is lighter too, which is designed to improve combustion efficiency and top end performance.

But the biggest thing for me as a racer is how easy this bike is to ride.

And I rode the 250 a lot on the test day, basically because I didn't want to get off it.

The French test track called Vinci Manoeuvre had everything you needed, fast and slow corners, long jumps, steep jumps the whole bundle.

The 250 just ate it up and Yamaha can be safe in the knowledge that the engine usability enhancements have worked.

You can really take the Mickey with this bike, push it hard and it won't turn and bite you.

It's funny really because I haven't been on a 250F for a couple of years but this new YZF made me miss riding the smaller machine.

By the end of the day I felt that if I decided to drop back to MX2 I could really be competitive on this bike.

The motor is fast and although the front forks were a bit soft for me I still felt well in control pushing the bike to its limits. I don't think that any purchaser will go far wrong if they choose to go blue for 2016.

I fell in love with the 250F and praise Yamaha for bringing a bit a joy to my heart...

I wasn't even sweating after so it was both a pleasure and not too hard on the old bones, the perfect combo for the club ace.

Well done to Yamaha overall on all its changes – big and small – they are on to a winner with the 2016 machines and if their GP and AMA boys continue in their rich vein of form, the club scene could well be turning blue in the coming months.

SPECIFICATIONS

2016 model Yamaha YZ450F & YZ250F (MX)

ENGINE

Type: Single cylinder, liquid-cooled, 4-stroke, with 4-valve DOHC, rearward slanting

Displacement: 449cc/ 250cc

Bore x Stroke: 97.0 mm x 60.8 mm/ 77.0 mm x 53.6 mm

Compression ratio: 12.5 : 1/ 13.5 : 1

Lubrication: Wet sump

Clutch: Wet, multiple disc

Carburettor: Keihin 44 mm EFI injection

Ignition system: TCI

Starter system: Kick

Transmission: Constant mesh, 5-speed

Final drive: Chain

CHASSIS

Frame: Semi double-cradle design

SUSPENSION

Front: Kayaba AOS USD telescopic fork/ KYB Speed-Sensitive System USD fork

Travel: 310 mm

Rear: Kayaba monoshock & link suspension

Travel: 315 mm

BRAKES

Front: Hydraulic single disc, Ø 270 mm

Rear: Hydraulic single disc, Ø 245 mm

TYRES

Front: 80/100-21 51M/ 80/100-21 MS32

Rear: 110/90-19 62M/ 100/90-19 MS32

DIMENSIONS

Overall length: 2,180 mm/ 2,170 mm

Overall width: 825 mm

Overall height: 1,280 mm

Seat height: 965 mm

Wheelbase: 1,480 mm/ 1,475 mm

Ground clearance: 330 mm

Fuel capacity: 7.5 litres

Oil capacity: 0.95 litres

Weight (w oil & fuel): 112 kg/ 105 kg

YZ250F – Changes for 2016

New lightweight piston

High specification con-rod

Optimized crank & balancer design

New ECU engine mapping

Larger diameter 270mm front brake

Refined clutch & shift mechanism

New style graphics

SPECIFICATIONS