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May 24, 2012
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We hear it all at MXA. Guys call to ask if we will test their 65 horsepower CRF250s. Guys call to say that we don’t know what we are talking about because they just bought a brand-new Gutbuster 450 and it’s fast not slow. Guys call us to ask if we think they could put a Kawasaki KX450F engine in a Husqvarna frame. Guys call us to say that they have ridden all the new bikes and there isn’t any difference between any of them. Occasionally, guys call and tell us that they are glad they waited for the 2012 MXA shootout because they love their new bike.

We appreciate all of the comments and impromptu backyard shootouts?but, just so you know, MXA starts with brand-new bikes. We don’t compare worn out bike and we don’t ride with someone else’s settings. Each test rider gets the bike setup to his tastes, even if that means changing springs and gearing.

But, most of all, we dyno every bike as soon as it is broken in. We use the same dyno for every bike (and have used the same dyno for years)?which means that all the numbers are comparable and accurate. No two dynos are alike…and you can’t compare dyno runs on bikes that are done on different dynos.

Here are the results of MXA‘s 2012 450 dyno runs. Rather than run the complete curves, we have included the horsepower at several points along the powerband ?and the peak number. Plus, we included ranking by rpm and a quick synopsis of what the power feels like.

 2012 450 HORSEPOWER NUMBERS BY RPM                      
BIKE                7000     8000       9000     10,000    11,000     PEAK HP
KTM 350SXF:   34.34     42.28      46.94      47.43       46.99       48.58 (12,200 rpm)
CRF450:          45.60     52.22      51.59      51.06       49.48       52.58 (8600 rpm)
KTM 450SXF:   46.15     52.11      52.85      51.14       49.01       53.22 (8300 rpm)
RM-Z450:        45.93     51.91      54.08      51.75       48.04       54.08 (9000 rpm)
KX450F:          47.22     53.59     55.45     51.46       44.76       55.50 (8900 rpm)
YZ450F:          44.78     50.48       55.24     53.43       50.76      55.24 (9100 rpm)

 HORSEPOWER RANKINGS BY RPM RANGE                              
7000 rpm (first to fifth):   KX450F,  450SXF,    RM-Z450,  CRF450,    YZ450F,  350SXF
8000 rpm (first to fifth):   KX450F,  CRF450,   450SXF,      RM-Z450, YZ450F,  350SXF
9000 rpm (first to fifth):    KX450F, YZ450F,    RM-Z450,   450SXF,    CRF450,  350SXF
10,000 rpm (first to fifth): YZ450F, RM-Z450,  KX450F,     450SXF,    CRF450,  350SXF
11,000 rpm (first to fifth): YZ450F, CRF450,   450SXF,      RM-Z450, KX450F,   350SXF
Peak HP (first to fifth):      KX450F, YZ450F,    RM-Z450,    450SXF,   CRF450,   350SXF

 2012 POWERBAND ANALYSIS                                                        

Kawasaki KX450F: The 2012 KX450F is a romping stomping good engine. It’s massive horsepower advantage down low allows it to launch out of corners at relatively low revs?which gets it up to speed in a hurry. And this bike is in hurry. Although it falls off at 10,000 rpm and 11,00 rpm, every MXA test rider felt that the gradual reduction in power didn’t hurt the overall performance. why? Because this bike is up to speed so fast that it does it best work while the other bikes are warming up.

Yamaha YZ450F: You would never guess from the saddle that the 2012 YZ450F makes the most peak horsepower, because it makes the least power from idle to 8500 rpm (because of it restrictive muffler choking off the power). Once at 9000 rpm the YZ450F comes into its own and has the strongest pull across the top. Many test riders felt that the power was a little late in the powerband, but that the mellow transition off the bottom to the strong mid-and-up made the powerband feel very long. Plus, the restrictive muffler made the YZ450F rev slower below the midrange?which was a plus.

Suzuki RM-Z450: This is a really good engine. It isn’t special or spectacular at any point on the curve, but it pulls over a wide range and very feels rushed. Every MXA test rider liked the spread of the power and felt that the output was adequate to get the job done.

KTM 450SXF: Thanks to the Keihin carb the KTM 450SXF produces the broadest, easiest to use and most manageable power of the group. It has the kind of power that works well at every rpm range. It never hits as hard as the Kawasaki, but it generates power as it goes and goes and goes. It has the longest overall powerband because it mates competitive horsepower with a metered rev. You can almost feel the engines vibes being transferred into the ground. It is the best 450 engine for average riders.

Honda CRF450: Someone has to make the least peak horsepower and in the 2012 class (only counting 450cc engines) that bike is the CRF450. We didn’t expect it to be fast because Honda made no changes to the engine from last year…and it was pretty mellow in 2011. That said, the CRF450 engine is very tractable, well modulated and pleasant to ride. It produces what one MXA test rider referred to as a “no-hit, no-rush, no-hurry” style of power. Because it revs predictably, the powerband is quite usable and riders were able to ride it harder than the could the bikes with bigger numbers.

KTM 350SXF: Roger DeCoster thinks that this is a very good bike for a rider coming out of the 250 class. That is why he put Marvin Musquin and Ken Roczen on 350SXFs when they raced in the 450 class (when they weren’t racing the 250 West). This isn’t a 450 motocross bike. It is a 350 and that means that it has to be revved (peak horsepower is at 12,200 rpm). Since it never tops 50 horsepower, it has to be ridden with more verve than a 450. At 236 pounds it isn’t light, but thanks to the high revs and the decreased rotating mass of the smaller piston, valves and crank it feels lighter than it actually weighs.


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