Racer X Tested: 2010 Yamaha YZ450F
September 21, 2009, 11:15pm
But that word is nothing new for the boys in blue. Or red. Or white. Back in 1997 they shocked the motocross world when Doug Henry showed up at the races with a YZ400F four-stroke. He won the 1997 Las Vegas SX, then used it to win the 1998 250cc MX title the following summer. The bike went against everything, but everyone soon followed. Yamaha then debuted a four-stroke to compete against the 125cc two-strokes. Mission accomplished with the YZ250F. They forced two-strokes into extinction, so what’s next for the YZ researchers? To reinvent the 450cc four-stroke from the ground up, even though it’s the motorcycle that currently holds one of the most prestigious championships in our sport — the AMA Supercross crown.
The Bike
Many months ago photos leaked online that were supposedly of the new YZ450F engine, with an exhaust was coming out of the rear of the cylinder. Many people shrugged it off as just a rumor. I know I did. Of all motorcycles I can remember, none ever had the exhaust coming out of the rear of the cylinder. Why? I don’t know, I’m not a mechanical engineer; it just made sense.
{LINKS}The 2010 Yamaha YZ450F goes against everything that I ever thought was sensible on a dirt bike, but after today, I’m, for lack of a better word, amazed.
Obviously, riders wanted an all-new redesigned YZ450F, because that’s what they got. Pretty much everything on this bike is new, changed or redesigned, with emphasis on keeping the weight of the heavy components towards the center of the machine. That crazy exhaust coming out of the rear of the cylinder is real, and Yamaha states that “it helps the engine achieve its exceptional low-to-midrange torque.” The pipe is located where the airbox used to be, so the airbox has been relocated to the front of the bike. This allows for a straighter intake which helps to keep dirt out, and we all know that’s what four-stroke engines love: clean air. To change the air filter, though, you have to pop the seat, remove two bolts from the gas tank and raise it up. I saw it done today, and it’s not too much of a hassle. It also makes valve adjustment a cinch, if you’re into that kind of thing.
The engine is slanted 8.2 degrees off the vertical axis toward the rear of the motorcycle, which is the most noticeable change to the untrained eye. (It also helps to keep the weight towards the center of the bike.) Inside the cases there’s a myriad of small changes—including going from five to four valves — dedicated to increasing the power in the low and mid-range. The cylinder is also offset 12mm from the crankshaft center which makes the connecting rod more vertical. What does that do? More efficient combustion. Duh.
This new 450 is now equipped with a Keihin fuel injection system, which provides awesome throttle response and offers some tuning options with a Yamaha GYTR Power Tuner. It retails from Yamaha for $279.95 and it allows you to adjust the air/fuel ratio as well as ignition timing. Just think, on the way to the track you could create a few different ignition maps to try out. Now that’s technology, and Yamaha is at the forefront.
Yamaha didn’t stop their redesign there, as the styling is really trick, and it’s available in either blue or white and red. We rode the white one today, and it comes with black rims. Who doesn’t love black rims? Regardless of the color, if you show up at the track with one of these things, people are going to take notice.
The Ride
What was most noticeable for me? To give you an idea about my riding skills, I’m an ex-pro privateer racer, but I’ve never really been able to get comfortable or feel confident on a 450. I’m 5’8” and weigh about 165, so 450s always felt heavy and cumbersome in the corners.
It took less than a lap on this bike to notice a huge difference in the turns, which is arguably the most important obstacle on a motocross track. I felt like I was on a 250F with the horsepower of a 450, which is crazy because this year’s model is actually heavier than the 2009 YZ450F. The power is very manageable, as the main emphasis for this year’s model was in the low to mid-range. It doesn’t rip your arms off, which is a huge advantage for your average rider. It settled into ruts nicely and was very nimble. Though the track wasn’t national-caliber rough, the suspension soaked up everything I threw at it, which included over-jumping more than a few tabletops today.
In closing, I really don’t have anything negative to say. It may be because I’m still high off of adrenaline from riding in pristine conditions today on nothing less than a revolutionary motorcycle. But I digress.
Well, I do have a complaint: Armpump and blisters, but this is the first time I’ve ridden in over two months, so I definitely don’t blame the bike. In fact, I was really surprised at how long I was able to ride, considering my lack of seat time.
I’ve been to a couple bike introductions before, but nothing like this. This bike is easy to ride, fast and fun, and I’d recommend it to riders of all skill levels. It retails for $7,990 and should be in your local Yamaha dealer sometime in November, so check it out, because there’s also a bunch of changes and improvement that I failed to mention. To watch the bike in action, stay tuned to Racer X Online later for a video from today.
