2010 Yamaha YZ450F | Doin' Time

Ringleader: Brian Catterson
MSRP (2010): $8090
Hours: 40
Mods: Acerbis hand guards, DeCal Works numberplates, Continental Gelande Sport and Dunlop Geomax MX51 tires

"It's time," read the subject line of Yamaha Media Relations Manager Tim Olson's email. "I hate to say this, but I need to get the YZ450F back from you."

Drat. Of course, I knew this day was coming. And symbolically, it came the same day Valentino Rossi first tested a Ducati MotoGP bike after seven years on Yamahas. I'm not going to kiss my YZ-F goodbye like Vale did his YZR at Valencia, but then there aren't millions of fans watching me on TV.

My YZ450F was the optional white model, which for $100 more than the standard blue version gives buyers black rims and a gold chain. Custom red number-plate backgrounds from DeCal Works ($62.45; www.decalmx.com) made the bike look "factory," even after I stuck REM stickers over the AMA Pro Racing logos to avoid looking like a poser.

Like every dirtbike my YZ looked great while factory-fresh, but after 20-odd race weekends it looks like it's been sandblasted! The black rims are now silver where they've been gacked by rocks and tire irons, and the gold chain has been replaced once, and will soon be due again, along with the sprockets. The white plastic has seen better days as well; particularly the side numberplates, the mounting tabs of which broke in crashes, leaving the plates flapping. Fortunately, it's a simple matter to pop-rivet them back in place.

Because I'm 6-foot-1, the first order of business was moving the handlebars to their farthest forward position. And because I weigh 215 lbs., I had the accessory stiffer fork and shock springs installed. Adjusting the damping to suit, I really couldn't complain about the suspension on the mostly "old-school" natural-terrain motocross courses I rode.

Early on, I used Yamaha's GYTR Power Tuner ($279.95) to tone down the abrupt off-idle hit, which let the bike hook up better off corners. Yamaha's recommended settings are posted online, and I ran the "Less Hit Feeling at Low RPM" setting. But after installing a Dubach Racing Development exhaust ($649.99; www.dubachracing.com), I was able to revert to the stock fuel and ignition maps. The DRD pipe not only tamed the bottom-end hit, but also gave the engine more over-rev on top. That helped compensate for the too-tall stock gearing, which makes for a big gap between second and third that lets the engine fall on its face when shifting going uphill or in heavy dirt. I ran the stock 13/48 gearing, but heard good things from riders who tried 49 and even 50-tooth rear sprockets.

My YZ was delivered with Dunlop knobbies, a D742F in front and a D756 in the rear, both good all-around "intermediate" tires. When those wore out I replaced them with Dunlop's latest Geomax MX51s, which worked even better in the soft sand at Glen Helen. Along the way I also tried Continental's new Gelande Sport Intermediate knobbies, which worked great in the soft stuff but gave the bike a tippy, falling-in feeling on harder dirt.

Of course, Glen Helen is also rocky, so I bolted on a set of Acerbis Uniko hand guards ($38.95; www.acerbis.it) to deflect roost. These were simple to install, look and work great, and never broke despite a relentless beating.

Maintenance was a mixed bag. With the airbox sandwiched between the engine and gas tank, and the seat having to come off first, getting to the air filter is a chore, particularly if you misplace the little wire thingamajig that holds the tank up out of the way. But once you get to the filter it comes right out, and its flat, square shape makes it easy to clean, lube and replace. Moreover, because the air intakes are high up behind the radiator shrouds, the filter doesn't live in the dirt thrown up by the rear tire, so it gets less dirty. You really don't have to clean it after every ride.

The valves were checked once at around 20 hours, and at double that figure are probably due again. The oil and filter were changed every five or so races-a pretty straightforward procedure. The spokes were presumably tightened at the original press intro and never came loose after that. The only actual problem I had was leaky fork seals, one of which oiled the front brake pads, rendering them useless. After replacing both the seals and the pads, I made it a habit to shove an Acerbis Fork Saver between the front tire and fender when tying down the bike. At $19.95, it's cheap insurance.

Powerful, fast, sweet handling, super-stable and virtually trouble-free, my YZ450F proved to be a worthy teammate, giving me a good reason to get out of bed early on weekend mornings. I still have yet to win at the Saturday REM races, but I did win the Modern class at the ARX vintage races one Sunday, so added to my trophy collection.

Maybe I'll kiss it goodbye after all...