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2010 Yamaha YZ450F: Another Paradigm Shift?

Somewhere, a long time ago, I seem to recall hearing that Yamaha was a “marketing company” and Honda an “engineering company”. Over-simplifications, even then, but now entirely untrue (at least as far as Yamaha is concerned). If the new R1 is a “paradigm shift” as a result of its cross-plane crankshaft, Yamaha has come back with another model that changes the rules . . . the entirely new 2010 YZ450F motocross bike.

With the cylinder slanted rearward, air intake in front, and exhaust outback (where nature intended it to be, perhaps) and a virtual ram-air effect on a motocross bike, the new YZ450F certainly gets your attention. The details don’t disappoint, either. The cylinder is slightly offset so that the connecting rod is vertical at the moment of combustion, thereby minimizing piston friction against the cylinder wall during the powerstroke. The four-valve, fuel injected engine sits in an entirely new “bilateral beam” frame that features a double S bend that purportedly improves handling.

No battery is necessary to power the fuel injection system with its 44mm Keihin throttle body and 12-hole injector spray. Yamaha claims the FI “provides optimal air/fuel mixtures in all altitudes and a wide range of temperatures for outstanding throttle response.”

This new engine has a new bore and stroke (97mm x 60.8mm) and a higher 12.5:1 compression ratio.

Together with the new frame, Yamaha designed a new swingarm that bolts to a new shock absorber that occupies space no longer needed for the front-mounted airbox. The fork is now 10mm longer to help balance the new weight distribution of the bike. The entirely new design, with its new weight distribution, also called for a change in fork offset (from 25mm to 22mm).

Yamaha says all of these radical features result in extraordinary mass centralization for a more nimble handling machine. Even the new fuel tank is positioned underneath the seat. The 2010 YZ450F will be available in Team Yamaha Blue/White, as well as White/Red. The plastic on these bikes has a more durable matte finish on high wear areas. Each of the colors will be available at your U.S. dealer beginning this month, with the White/Red priced at $8,090, and the Blue/White at $7,990.

I am told Supercross champ James Stewart likes his new bike. MD will be among the first journalists to test it.

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MD Readers Respond:

  • Like it. Want it. *IF* they can just make a WR version that is STREET LEGAL. If KTM, Husky & Aprilia can do it, why can’t the Japanese brands? Last time I went on a dual-sport ride here in CA, it was a sea of orange. As I understand it the 2010 BMW 450X will also be street legal here in CA. I am not aware of any Japanese 450 that is street legal here in CA (please correct me if I’m wrong). tony
  • Now give the bike 6 gears, more than 1/2 quart oil capacity, valves that don’t need adjusting once a week. Have GYTR sell those 450 super single kits.
  • Was this report written by a new staff member? One who spent the last 37 years at “Bras and Girdles”? George
  • Tell Yamaha I (& probably many other trail riders) would likely be unable to resist buying the WR450F version of the 2010 YZ450Fie if/when it appears (hopefully soon). jimbo
  • Yamaha was a “marketing company” and Honda an “engineering company”. Like it or not, that statement was made by someone who obviously ignores Yamaha history of trend setting firsts. I’m not saying that they were the only company to try these new ideas, in fact, like most of todays good ideas, they’re recycled but can now be successfully done do to technology. I think if you compare how many mass produced design ideas Yamaha is responsible for, Honda pales in comparison. My 1994 GTS 1000 was a very innovative bike, but due to the fact that the US market was not ready to pay $13,000.00 for a Japenese motorcycle, it never took off. Let’s consider who brought you things like; Monocross (single rear shock); YPVS (powervalves on two strokes); EXUP (powervalves on four strokes); Deltabox (twin Beam frame); 17′ wheels on sport bikes; Genysis (five valves per cylinder, which Honda then went and took patons out on other valve configuration not knowing that Yamaha had already tried these);

    The list goes on, even the Big Bang GP engine was tried by Yamaha back in the early eighties but dropped because of engineering hurtles at the time. I would challenge the person who made that statement to name all the ideas that Honda put on the market in which have become the norm for the industry. But just like most things today, perception is more important than reality. If you ask me, and look at it honestly, I think that statement is actually backwards. Daniel

  • Engine sounds somewhat like Cannondale’s attempt at a motocross bike a
    dozen or so years ago. Gregory