With a tank-empty weight of just 231 pounds, the Yamaha also proved to be the quickest steering of the bunch.
The near-endless and totally usable power of a 4-stroke is one of the reasons off-road riders are drawn to Thumpers like journalists to free food. The introduction of the Yamaha YZ400F was a revelation because it demonstrated 4-stroke machines were not only powerful, but they provide tractable power throughout the rev-range.
These machines have upped the ante once again. With more muscle available, throttle jockeys around the world now have more gas-laden clout than they could possibly need. Yet, wanting more horsepower and needing it are two different things. Most riders will never come close to using all the horsepower any of our four Thumpers can provide.
Yamaha seemingly went off the deep end with the over-the-top 449cc liquid cooled, single cylinder, titanium 5-valve powerplant. It’s clear Yamaha intended to win the horsepower war.
Since you can determine how much power a bike has by riding, nothing reveals exactly what’s happening like a trip to the dynomometer. So we trucked our foursome out to our friends at White Brothers for some high-rpm mayhem on their state-of-the-art Dynojet dyno.
As intimated above, it was the YZ450F that emerges as the horsepower king. Screaming up to 9000 rpm, the YZF cranks out 49.0 horsepower, slightly better than the second-place Honda CRF450R, which topped out at 47.6 horsepower. The Honda produces its peak horsepower at a lower 8250 rpm thanks to a new camshaft that shifts power 500 rpm lower than last year. The other two bikes have their horsepower peaks at 8500 rpm, with the KTM squeezing out 45.6 horsepower and the Cannondale a respectable 40.6 ponies.
The Yamamonster puts out more horsepower than the rest of the group once past 4500 rpm, and it retains that advantage all the way to redline. Unfortunately for Yamaha, big numbers on the dyno don’t automatically make for the best bike in real world situations. That would be decided once we took the quartet at three quite different tracks. First stop, the impressive Racetown 395 track in Victorville, CA, followed by a day at the famous Glen Helen circuit in San Bernardino and before the finale at Lake Elsinore Motocross Park.
Before anyone can experience the bulging power of a big-bore 4-stroke, the first task is to get it fired up. Anybody that has a ridden a big Thumper in the past is aware that starting one of these beasts can be a real pain in the ass.
Honda alleviated the kickstarting concerns when it introduced the 2002 CRF450R with an automatic decompression system. Riders bring the engine to life with just one or two kicks, no extra steps and no worries about the high-compression motor kicking back. This is convenient in the pits, but it’s even better when you stall on the side of a hill or in the middle of a race. Yamaha and KTM took note and implemented the automatic decompression on their latest bikes. This is a big improvement, as kicking the YZF in the past could be a frustrating proposition.
The blue line rising above all the others is the amazing YZ450F that has a power advantage over most of the rev range including the most peak power.
As easy to start as the above trio is, one bike stands out. The Cannondale X440’s 439cc engine is brought to life with not a kick, but with the simple push of a button. The legendary bicycle manufacturer turned moto-maker includes an electric start on their machine, which is sinfully easy to get used to.
Stalls are seldom a bother on this American-made machine, but the convenience comes at a price. The aluminum-framed Thumper weighs in at a whopping 258 pounds on our electronic Intercomp scales we procured from the extensive White Brothers catalog. That’s 23 more than the aluminum-framed CRF (235 pounds) and 24 more than the KTM (234 pounds). Least in need of assistance from Jenny Craig is the YZF that scales in at a svelte 231 pounds. You’ll notice the two bikes with steel frames are the lighter than the alloy-framed pair.
Part of what makes the Yamaha so light is the loss of fifth gear from the shorter-stroke YZ426 model. Further reducing weight, as well as making the engine quicker revving, are the lighter-weight titanium valves, short skirt pistons, and a lighter crankshaft. Lighter, too, are the frame, tapered swingarm, bash plates, brakes and, probably, the spark plug. These and other changes made the 450F the most anticipated bike among our four testers.
2003 4-Stroke Open MX
2003 Yamaha YZ450F Comparison
2003 Honda CRF450R Comparison
2003 KTM 450SX Comparison
2003 Cannondale X440 Comparison
2003 4-Stroke Open MX Conclusion