While yours truly is not known for his motocross abilities their were several Pro riders on hand, Nic Granlund and Kory Ellis, to make sure the YFZ450 was put through it's paces. We showed you all the details last month. Now it was time to see if Yamaha had really put all of the pieces together so that this bike works like it should.

We started in the morning on stock production YFZ450's just like they will sit on the showroom floor. No GYT-R parts added. The machine was comfortable to sit on and the ergonimics of the YFZ450 are very nice. The seat is flat and did not feel odd like the Polaris Predator. The seat and tank also narrow nicely in the front so that your knees have room unlike a Cannondale. The front fenders were far enough foward so that even the tall riders had room for their knees. The emergency brake, as odd as it looks, is actually quite functional and works better than most we have used. Although I am sure it won't stay on many race bikes very long, Yamaha has made it easy to remove and still keep the adjusatble YZ clutch lever in place.

Firing up the YFZ450 reveals a very mild sounding powerplant. Noise is a big issue in many areas and in stock form the YFZ450 is VERY quiet putting out only 82db. Yes the YFZ450 does meet all emission requirments and IS eligible for a green sticker in California.

On the Track

Initial impressions were very good. The YFZ450 had excellent acceleration. Power felt better than a Z400 and more in range with a Polaris Predator or a modified Z400. Acceleration is excellent and the transmission feels very smooth and the ratio's feel right on. The power is good throughout the powerband with no peaky spots. The clutch pull feels good and is adjustable with the emergency brake off and out of the way. At 350 lbs the YFZ450 felt light and balanced. The Pro Riders in attendance were easily clearing all of the doubles and table tops with the exception of two that had a very short take off. The suspension felt good and did not draw any major complaints from any of the riders in attendance. Some talked of minor tweaks to get the suspension to their liking but all of that can easily be accomplished since the YFZ450 features fully adjustable compression and rebound all of the way around. The only minor complaint I had was that muddy spots on the track made from the watering seemed to end up directly on my goggles. Another bike may do the same thing also but it was anoying and called for roll offs even with only a few muddy spots.

Time for some GYT-R tweaks

At this point it was time for some lunch and time for the Yamaha folks to do some tweaking on the YFZ450. Each of the YFZ450 test bikes were equipped with a GYT-R header and silencer, rejetted with a GYT-R jet kit, and had the airbox lid removed. The modifications took about 20-30 minutes per ATV and were performed trackside.

I have ridden a number of sport quads with stock configuration and then with jetting and a pipe. The difference is usally noticeable but not in a huge way. Firing up the modified YFZ450 revealed a much louder and powerful sounding motor. The GYT-R pipe is said to put out 102db. ( A silent core module is in the works that will bring it down to 96 db.) By the time I was half way down the first straight away I had a HUGE smile on my face. It was hard to believe I was on the same bike. The YFZ450 was nothing less than incredible with the GYT-R pipe, silencer, jetting, and open airbox. Acceleration was good before but NOW the YFZ450 ripped!

Summary

After spending a full day of riding the YFZ450 we are still VERY impressed with what Yamaha has produced. The overall package when GYT-R race equipped is sure to turn the race tracks blue in no time. If you are a pure trail rider the Raptor may still be your best choice, but if your a racer you better get down to your Yamaha dealer and order a new YFZ450 equipped with the GYT-R pipe, silencer, jet kit, and open airbox.

Yamaha Motor Corporation, USA
www.Yamaha-Motor.com