Yamaha’s YZ450F made a major breakthrough in 2015, the tuning fork brand hitting on just the right combination of minor tweaks to put its YZ450F at the top of the 450cc moto mountain.
After a major revamp in 2014, the 2015 not only out-performed its rivals in shootouts, it outperformed them in showrooms, with Yamaha boasting a 30% increase in YZ450F unit sales year-to-date compared to 2014. The 2015 YZ450F is currently the best-selling 450cc motocross machine on planet Earth.
But as good as the 2015 model is, Yamaha has found ways to make the YZ450F even better for a wider range of riders in 2016, and another round of minor updates seems to have done the trick. The 2016 YZ450F is still fast, but it is now easier to ride than ever, and it handles better than the 2015 model. If our day spent aboard the 2016 YZ450F during Yamaha’s U.S. press intro at Southern California’s Competitive Edge Motocross Park is any indication, Yamaha doesn’t plan to relinquish its best-selling status without a fight.
Interestingly, some of the changes that make the 2016 model better than the 2015 sort of travel in the same knobby tracks already laid by Yamaha engineers last year, or at least they are continuations of the same. The revision list in 2015 included an ECU tweak (to fatten up its fuel-injection at low rpm for a smoother throttle feel), bigger valves, lower motor mount changes, a slight gearing change, stiffer fork springs and suspension setting refinements. For 2016, Yamaha has refined the engine even more, retuned the chassis flex and juggled the suspension damping specs again to make the brutish 450 a little more user-friendly. But there’s also a new trick in the form of a new Launch Control System to help harness the 450cc’s thunderous power out of the starting gate.
The key to making the YZ450F’s 449.7cc, liquid-cooled, fuel-injected DOHC engine a bit more usable for vets and less skilled riders lies in the cams. The engine’s 97.0 x 60.8mm bore and stroke and 12.5:1 compression ratio are unchanged for 2016, but to give the motor more robust low-end torque and a smoother transition through the rev range without hurting its mid-range and top-end performance, the 2016’s intake and exhaust cams feature different lift, duration and lobe centers that change the timing with which the 450F’s titanium intake and exhaust valves open and close. According to Yamaha these are the specs for the 2015 and 2016 cams.
|2015 YZ450F Intake Cam||2016 YZ450F Intake Cam|
|Open: 37° BTDC||Open: 30° BTDC|
|Close: 77° ATDC||Close: 78° ATDC|
|Lift: .377”||Lift: .374”|
|Duration: 294°||Duration: 288°|
|Lobe Center: 110° ATDC||Lobe Center: 114° ATDC|
|2015 YZ450F Exhaust Cam||2016 YZ450F Exhaust Cam|
|Open: 73° BBDC||Open: 70° BBDC|
|Close: 43° ATDC||Close: 38° ATDC|
|Lift: .346”||Lift: .358”|
|Duration: 296°||Duration: 288°|
|Lobe Center: 105° BTDC||Lobe Center: 106° BTDC|
The change in the numbers may not seem all that radical on paper … er, onscreen, but the new cams do make a noticeable difference in the overall performance of the YZ450F. According to our ace test rider, Ryan Abbatoye, the 2016 YZ450F now comes off the bottom smoother and with more authority than the 2015, making it easier to get a good drive out of tight corners. The extra grunt also makes for a more seamless transition to the top-end rush. The slightly less explosive power delivery at low rpm should increase confidence in riders making the transition to the YZ450F, but pros needn’t worry about a lack of sizzle. Abbatoye said that the bike feels just as strong through the middle and on top as last year’s YZ. The only difference he noted is that the 2016 doesn’t rev quite as quickly as the 2015 did. Still, the YZ450F delivers more power than most mortals can tame, and the slightly abnormal Abbatoye amply showed off the bike’s true potential as he nuked berms and soared off of Comp Edge’s numerous jumps. The Yamaha is clearly still a beast, just a more manageable beast.
Yamaha also made improvements to both the YZ450F’s clutch and five-speed transmission for 2016, incorporating a new machining process claimed to make the surface on the clutch basket as flat as possible in an attempt to improve the clutch engagement feel and also changing the shift stop lever design and shifter dog shape. The new shift stop lever increases spring load by 20% compared to the previous model, which Yamaha says will make shifting more precise under power and also reduce the chance that the rider will catch neutral on the 1-2 upshift. We never had an issue with the way the YZF shifted in 2015, but Abbatoye noted that the 2016’s shifting feels smooth and precise especially under full-throttle upshifts without using the clutch. The only other internal engine change Yamaha engineers made for 2016 was to add six holes to the water pump impeller to improve pressure distribution within the pump and thus make the system less prone to blowing a water pump seal.
The YZ450F’s new Launch Control System is designed to offer the same benefit as the systems found on competitive models – to get the rider out of the gate more effectively. The system works in concert with the ECU to briefly retard ignition timing and thus limit wheelspin on slippery concrete or slick dirt launch pads. It is engaged by pressing a button on the left handlebar, and a flashing red light denotes when the system is armed. The system works in either first or second gear, and the ECU reverts to the standard map when the rider shifts into third gear.
Abbatoye spent some time getting to know the 450F’s Launch Control System at Comp Edge. On the track’s slick concrete starting pad, the LCS made second-gear starts easier, and the machine moved out more quickly than it did when Abbatoye made his baseline starts with the system disarmed. However, in the dry, loose, deep, dirt just ahead of the starting gate, the system tended to flatten out the power too much to make it truly effective. Abbatoye found that he was better off simply using the old-school, slip-the-clutch method to control wheelspin rather than relying on the LCS to do it for him. The Launch Control System certainly works when conditions are really slippery, but we’d call it a qualified success.
Yamaha tweaked the YZ450F’s chassis to improve its handling characteristics for 2016, once again altering the flex character of its Bilateral Beam aluminum chassis but also adjusting the fork offset to deliver more front-end feel and better turning stability. To attain the desired rigidity, the 450F’s frame spars have been made 12mm wider at the swingarm pivot and also added new top motor mounts that feature more of a v-shape than the previous y-shape and a thicker cross section (8t vs. 6t) than the 2015’s mounts. Lastly, Yamaha incorporated new footpegs that are 5mm lower than the previous models without actually changing the footpeg mount on the frame. This was done to increase rider comfort and also, says Yamaha, to lower the YZ450F’s center of gravity.
To directly address the front end feel in the corners, the 2016 YZ450F gets a new top fork clamp with 25mm of offset, 3mm more than the previous version to effectively pull the forks in closer to the steering tube. However, at the same time, the rear shock spring is softer – Yamaha dropped its spring rate from 58Nm to 56Nm, effectively allowing the rear end to settle more under a load, which actually increases trail. The 2016 YZ450F’s 58.3-inch wheelbase is the same as last year’s bike.
Abbatoye, who weighs 160 lbs. in full gear, commented that compared to the 2015, the 2016 YZ450F delivers a more balanced feel in the corners and is more stable. Whereas last year’s model tended to sit with more of a tail-high, stinkbug stance, the 2016’s chassis feels more settled while still delivering sharp turning manners. While we noted a slight nervousness in the 2015 YZ front end when diving into corners, the 2016 is far more confidence-inspiring. Abbatoye was able to charge the corners harder because the ’16 goes where you point it more precisely than before and with minimal effort. It also dutifully follows deep ruts without any issues.
The spring change to the YZ450F’s KYB piggyback (which offers preload, high- and low-speed compression damping, and rebound damping adjustability) shock also yields a more harmonious interaction between the front and rear suspension in rough ground, with 12.4 inches of cushy travel. Up front, Yamaha has stuck with its tried-and-true 48mm KYB Speed Sensitive System (SSS) fork, which features good ol’ steel coil fork springs, instead of air to deliver 12.2 inches of travel, and we applaud them for it. The fork is easy to tune and offers ample compliance over small bumps while resisting bottoming over big jumps. The revised suspension and chassis settings had our test unit tracking straight and true through Comp Edge’s whoop section.
The 2016 YZ450F’s new 270mm petal-style front disc brake is about the only improvement that leaves us indifferent. While it is 20mm larger than last year’s front brake, Abbatoye said that he really didn’t notice any increased performance out of it when compared to the previous front brake. The brake delivers a linear feel, and its stopping power is more than adequate, but it’s nothing that is going to make Honda or KTM run back to the drawing boards.
Then again, maybe the 450F’s ergonomics will. Yamaha’s strict attention to mass centralization allows for a roomy cockpit with a flat, narrow seat and practically seamless transition to the top of the “fuel tank” (which is actually the top of the airbox, since the 2-gallon tank is under the seat). Abbatoye quickly noted that lowering the footpegs 5mm makes a substantial difference in comfort, allowing him to feel completely comfortable when whipping the bike around to his heart’s content.
Yamaha has chiseled away the YZ450F’s rough edges over the past year, making small improvements that have increased its performance and its popularity. The 2016 YZ450F is proof that you can make a great bike better.
|2016 Yamaha YZ450F Specifications|
|Engine Type:||449.7cc liquid-cooled DOHC 4-stroke; 4 titanium valves|
|Bore x Stroke:||97.0 x 60.8mm|
|Fuel Delivery:||Yamaha Fuel Injection (YFI), Keihin 44mm trrottle body|
|Ignition:||TCI (Transistor Controlled Ignition)|
|Transmission:||Constant-mesh 5-speed; multiplate wet clutch|
|Front Suspension:||KYB Speed-Sensitive System, inverted fork; fully adjustable, 12.2-in. travel|
|Rear Suspension:||KYB monoshock, adjustable preload, compression and rebound damping, 12.4-in. travel|
|Front Brakes:||270mm rotor disc brake w/two-piston caliper|
|Rear Brakes:||245mm rotor disc brake w/single-piston caliper|
|Front Tire:||80/100-21 Dunlop MX52-FA|
|Rear Tire:||120/80-19 Dunlop MX52|
|Seat Height:||38.0 in.|
|Ground Clearance:||13.0 in.|
|Fuel Capacity:||2.0 gal.|
|Claimed Wet Weight:||247 lbs.|
|Color:||Team Yamaha Blue/White; Limited-edition 6|