Test Ride: 2014 Yamaha YFZ 450R

Changes make a great sport quad even better

September 2013 Powersport News By Dustin Pancheri, For Dirt Toys Magazine

Assembled in the U.S.A. That's a point Yamaha continually emphasized as the company introduced us to the 2014 YFZ 450R. Of all the new features that Yamaha could have bragged about, it chose to start off with the fact that Yamaha has moved production of the 2014 YFZ to its new state-of-the-art 875,000 square-foot facility in Newnan, GA.

Why is this important to us you ask?

Promoting business, creating jobs and helping the U.S. economy are the easy answers. But for the ATV community it proves that Yamaha is focused on the American market; building specialized equipment designed for our specific needs.

Want proof? Look no further than the changes made to the 2014 YFZ 450R.

For those who skim, the 2014 YFZ has more power, a revolutionary new clutch, suspension changes, improved ergonomics, plastic changes and changes to the fuel injection system. For those who like details, here you go:


Yamaha re-engineered the powerplant for 2014, giving the YFZ a significant horsepower boost. The company started with a new, longer connecting rod that attaches to a larger lower rod bearing. At 108.25mm this .25 mm longer rod does not change the stroke but moves the piston closer to the head, increasing the overall compression ratio. Up from 11.4, the new 11.8 ratio increases the power from the bottom of the powerband all the way to the top.

A new head and camshafts also add bottom- to mid-range performance while maintaining optimal top end pull. To give the motor power throughout, Yamaha changed the throttle valve from a No. 50 to a No. 100. This also made for a more solid power delivery off idle, giving the motor a more aggressive feel.

To meet the new 2014 emissions standards, Yamaha added an Ai system, which recycles clean air back into the exhaust to help burn any unused fuel that may have exited the motor. This system maintains the same power as if it were not on the machine with the only side effect being the addition of a couple additional hoses. To finish it off, the YFZ received new ECU calibration for precise fueling and timing.

Drive Train

Rarely do we see major changes in this area but for 2014 Yamaha has developed a revolutionary new clutch it calls the A&S (assist and slip) clutch. Don't think that this is hand-me-down technology from the dirt bike or road bike guys. Nope, this is a brand new design making its debut in the sport ATV world. Here is the scoop .

The clutch uses three pressure springs instead of the typical five or six found on most clutches. This reduces clutch pull by 25 percent, which was instantly noticeable the first time we tried it. There is way less effort to pull. So how does the A&S clutch maintain plate pressure while only using three springs?

Yamaha developed a rubber dampened opposing ramp system that fits inside the hub. As rpm increases, the ramps push together, applying increased pressure to the discs. When the throttle is released, the ramps disengage, removing the pressure which allows the plates to slip. An added bonus is that engine breaking is reduced which means less rear tire hopping and higher corner entry speeds. The result is a manual clutch that is smoother, has more control and is less tiresome than any clutch we have ever tested.


For 2014 Yamaha made minor, yet noticeable suspension changes. For the front the refinement process involved utilizing the existing KYB shocks with 9.8 inches of travel, high/low speed compression damping, rebound damping and Kashima coating. The front shocks were then extended 2mm longer for increased suspension stroke which helped with bump absorption and anti-bottoming characteristics. Yamaha then re-calibrated the settings to be optimal with the new length. The rear utilized the same highly adjustable KYB unit found on the 2013 but again adjusted the settings to work with the new front end calibration.


Yamaha's main focus was to build a machine that was primarily focused on motocross but could still handle some trail and off-road terrain. They accomplished this by using 21x7-10 Maxxis radials on the front and 20x10-9 Maxxis radials on the rear. The result was a tire that was low enough to corner well, yet had decent clearance for off-road use. But if you want a set you will have to go directly to a Yamaha dealer as this tire will exclusive to them for 2014.


One of the biggest surprises on the new model was the changes to the chassis in order to make the cockpit more roomy. Yamaha moved the front fenders forward 30mm and dropped them 10mm to give the rider more room to move. They also moved the footwell back 30mm, complimenting the changes made to the front. This was done in an effort to make the rider's side-to side transitions smoother.

Yamaha added a raised section to the rear of the fender by the seat so that the rider didn't drop when sliding half-way off the seat in corners. They then flattened the profile of the fender to complete the look. A small plastic cover was added to the frame below the tank to keep riders' knees from rubbing on the frame and give him a smooth transition from the tank down. The finishing touch was the installation of clips to fasten the plastic onto the chassis. No more screws or bolts on the plastic, meaning no tools are required to remove the body work. Yamaha even incorporated more space for sponsor logos and graphics.

New bar mounts with adjustable mounting points were incorporated. The bars can be moved in 10mm increments for a total of 20mm forward or 10mm rearward from the stock position. Our taller riders preferred moving them 10mm forward in order to get farther forward on jumps and some corners.

Performance Enhancements

Yamaha now has a full line of GYTR accessories for the YFZ that make it a much more capable racer on the weekend. Some of these parts like the GYTR head are developed in house and are not other companies' re-badged product. Others are co-branded to give the consumer a full line of accessories.

Our favorite of the bunch has to be Yamaha's full line of engine products that, when used together, really wake up the 5-valve engine. Those upgrades include a full exhaust, air intake, cams, ported head, high compression piston and a PCV fuel controller for proper calibration. The use of these upgrades together requires running higher octane race fuel like U4.4 or equivalent. Of course keep in mind if you plan on spending the extra coin for the head and cams you will want to make sure you have the rest of the components as well. Doesn't make much sense to open up the airflow on the head and still try to stuff it all through the stock intake and exhaust.

Other GYTR items include a front bumper, combination nerf bars/adjustable pegs, clutch cover, skid plate, engine plugs, chains, sprockets ... you get the point.

Rider Impressions

Yamaha has done a great job of building a race ready YFZ. The suspension calibration is almost dead on for most of our riders on your average track, which is one of the hardest things to do. The power is good and very controllable. It doesn't wear out the rider, yet will clear about any obstacle with the touch of the clutch. Add the GYTR kit and you can clear it even easier ... much easier.

The chassis feels good with plenty of room to move around. Our tallest test riders are 6-foot-3 and even they could freely move around. They prefer the combination nerf bars/pegs as the pegs are wider and longer than stock and can be adjusted down either three-quarters of an inch or 1.25 inches, which helps the tall guys a bunch.

The small changes to the plastic were noticeable on the track and proved to require less effort when changing from side-to-side or sitting-to-standing. Handling is good as the machine is predictable and stable while still remaining agile. The wider axle and low center of gravity keeps the machine flat in the corners.  We like the adjustable bars and took advantage of them when fine tuning our rider positioning. We like the Maxxis tires but wish the YFZ came with an 18-inch version as we could feel the tires roll on the rim. This of course is an easy change for anybody who plans on spending the majority of their time on the track.

The 2014 is the best YFZ we have ever ridden and think most people will agree. Dealers should be seeing them on the floor soon which will allow you to check one out for yourself.

Yamaha wants $8,799 but that's pretty reasonable when you consider you're buying American made.

2014 Yamaha YFZ 450R

Engine Type 449cc, liquid-cooled w/fan, 4-stroke, DOHC titanium 5-valve

Bore & Stroke 95.0 x 63.4mm

Compression Ratio 11.8:1

Fuel Delivery Yamaha Fuel Injection (YFI), 42mm

Ignition TCI: Transistor Controlled Ignition

Transmission 5-speed manual clutch

Drive Train 2WD; sealed O-ring chain, eccentric adjustment

Suspension/Front Independent double wishbone w/Kashima coated piggyback shocks, High/Low speed compression, rebound and threaded preload adjustment, 9.8-in travel

Suspension/Rear Cast aluminum swingarm w/ piggyback High/Low speed compression, rebound and threaded preload adjustment; 11.0-in travel

Brake/Front Dual ventilated hydraulic disc, twin piston

Brake/Rear Wave-style ventilated hydraulic disc, twin piston

Tire/Front AT21x7-10 Maxxis

Tire/Rear AT20x10-9 Maxxis

L X W X H 70.7x48.8x41.9 in

Seat Height 31.9 in

Wheelbase 50.0 in

Ground Clearance 9.3 in

Fuel Capacity 2.6 gal

*Wet Weight 405 lbs.

Color Team Yamaha Blue/White

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