Taming the Beast: A Year with the 2015 Yamaha YZ450F

MotorcycleUSA Staff | July 6, 2015

Subtle changes to the 2015 YZ450F brought about significant improvement for Yamaha’s 450 MX platform compared with the 2014 model. Adding flex in the right places, new engine mounts and upping the fork spring rate created a more stable and planted chassis, giving the 2015 YZ450F the best handling characteristics yet. MotoUSA hung onto the 2015 YZ for a long-term evaluation, and after a year in the saddle we’ve come back to report our observations prior to the 2016 YZ450F’s release later this month.


2015 YZ450FMellowing out the hit made the YZ450F easier to ride. Dirt Digits numbers made it look better. 

A full year of moto and dabbling off-road aboard the 2015 YZ450F taught us a few things. First and foremost, the 2015 YZ450F is a monster in the power department. It is flat out gnarly! For experienced riders and pros the instant power delivery is awesome, just watch the outdoor nationals and see how many blue bikes are up front on the starts. But for the average rider the 2015 Yamaha YZ450F can be a bit of a handful, so we went about mellowing out the power and making the 2015 YZ450F easier to handle and more fun to ride for the average rider.

Riders who own a fuel-injected Yamaha YZ450F, YZ250F, YZ250FX or WR250F need to own a GYTR Power Tuner. At only $279.95 it is the most effective tuning tool you can own. To mellow out the initial hit of the 2015 YZ450F we used our Power Tuner to install what Yamaha calls the Smooth Linear/Slippery Condition map. Instead of changing the fuel delivery, it retards the timing to produce ultra smooth power. You can also tweak on each cell, fine tuning the map even further. We suggest trying out a few different maps, the difference is immediate and completely changes the character of not only the engine but the handling as well. It takes less than 30 seconds to switch the map once programed into the Power Tuner so changing maps is ultra simple.

GYTR Power Tuner The GYTR Power Tuner is a very cool tool and makes engine tuning very easy.

The GYTR tuner maps are found on www.yamaha-motor.com. The GYTR Power Tuner page lists a break down of the different maps and a good tutorial video on how to use the power tuner. You can also print out a PDF of the different maps to keep with your power tuner. We’ve more than once used our iPhones to go to the website and find the maps while at the track.

Rekluse Core EXP 3.0The Rekluse Core EXP 3.0 auto clutch provides ultra smooth power delivery and prevents stalling. 

The Rekluse Core EXP 3.0 auto clutch boosts the ease of use and reduces the level of intimidation from the powerful 450. The EXP auto clutch virtually eliminates any chance of stalling and allows the rider to ride a gear higher, rolling on the throttle while the auto feature of the clutch smoothly delivers power to the ground, increasing bite as the rpms climb. If you didn’t know the MotoUSA 2015 YZ450F was equipped with a Rekluse you would just think it delivers ultra-friendly, but still very strong power. The feel at the clutch lever is like stock so you can still use it like a normal clutch if you choose, but chances are once you get used to how well the Rekluse puts down power you’ll reduce clutch lever use. Not only does the Core EXP smooth out the power delivery, the inner hub and pressure plate design flows more oil, keeping the clutch components cooler, which makes them last longer.

2015 Yamaha YZ450FAn FMF PowerCore 4 slip on muffler provided smooth power and comes with a spark arrestor. 

Another effective way to change the power character and the noise output at the same time was the use of an FMF PowerCore 4 aluminum slip-on muffler with a spark arrestor insert installed. We also ride at a state run track that requires a spark arrestor, so the PowerCore 4 is perfect, plus it provided a very similar power cure to the stock system but at a lower decibel level. If you really need to knock down the sound level FMF sells a quiet insert for the PowerCore4.

2015 Yamaha YZ450The 2015 Yamaha YZ450F is one fast motorcycle and MotoUSA made it easier to ride. Renthal chain and sprockets replaced stock. 

MotoUSA’s modifications to the YZ450F might seems counterproductive to those riders who feel it is all about horsepower but big power means nothing if you can’t get it to the ground in a controllable way. The YZ450F offers massive amounts of power for top level guys or larger riders who can utilize it, but the truth is there are a lot of riders who just want more than a 250F offers but don’t need all that a 450F gives. With the Power Tuner the YZ450F offers a wide variety of power deliveries, making it an excellent choice. With our changes the 2015 YZ450F still puts out plenty of power, it just does it in a friendly way without tiring us out as fast. The end result is a bike that goes faster the farther you turn the throttle, not one that wants to jump out from under us at a moment’s notice.

MotorcycleUSA Staff