WE RIDE WISECO PERFORMANCE’S YAMAHA YZ450F:

On Mar 1, 2009 Last updated Feb 24, 2018

The MXA wrecking crew likes to explore all the possibilities when it comes to motorcycle hop-ups. Whether it is testing James Stewart’s undefeated National bike, the production 2009 Yamaha YZ125, or Wiseco Performance Products’ YZ450F, we believe that you can’t tell good from bad without throwing a leg over all the options.

We must tip our caps to the folks at Wiseco Performance Products. Not only do they believe in their workmanship and products, but they were willing to let the MXA wrecking crew fly into their corporate offices in Ohio, thrash their pristine new Yamaha, and then race it. That’s like throwing fresh meat into the dog pound. We hate to admit it, but rarely does a test bike return to its owner in mint condition. Sadly, we have crashed the most exotic works bikes in the world (often just a few days before Chad, Travis, Ricky or James were scheduled to race them in a National). Such was the case with the Wiseco-built Yamaha YZ450F. After all was said and done, Wiseco’s museum-quality YZ450F had a broken left radiator (thanks to a fist-sized rock in a race), roost-rattled plastic, and some hard hours on the engine components. Amazingly, Wiseco was tickled pink about us ruining their purpose-built YZ450F. Why? The Wiseco bike that we tested wasn’t some special project that can never again be duplicated. Instead, it was a carbon copy of the work that Wiseco sells to the consumer every day. Every part on the Wiseco bike is available to the public.

Wiseco’s goal in letting MXA wear out their bike was to show us how well their engine modifications performed. The good guys at Wiseco didn’t care if we left the bike in pieces, as long as we were satisfied with the improvements they made to the machine.

SHOP TALK: WHAT’S IT ALL ABOUT?

What’s one of the coolest aspects of testing a bike built around the services of an aftermarket company? The ability of the company, in this case Wiseco, to pick and choose the parts, products and partners that they believe offer the greatest enhancements to their project bike.

In the case of Wiseco’s Yamaha YZ450F, 12 different aftermarket companies were enlisted for their services. Wiseco, of course, supplied the most components (high-compression piston, gaskets, clutch basket, inner hub, pressure plate, fiber plates, drive plates, clutch springs, clutch cover, intake cam and exhaust cam), while Renthal also made significant contributions with TwinWall handlebars, half-waffle grips, Intellilever clutch lever, sprockets and chain.

A Boyesen Supercooler kit was mounted, as were a Power Wing, Quickshot2 and Shokout clutch mechanism. DR.D understands YZ450Fs better than most, and the “Doctor” helped Wiseco with an exhaust system, radiator lowering kit and hour meter.

To help set the Wiseco YZ450F apart from nearly every other Yamaha on the track, white Cycra plastic spruced up the look. Other aftermarket items included a Tamer holeshot device, Fluidyne radiators, CV4 radiator hoses, Braking rotors, Pro-Wheels and Michelin tires (S12 front and M12 rear). Like any present, the gift must be wrapped in something that’s decorative and appealing. That’s where Johnny Signs came in. The graphics company made a custom kit for the Wiseco YZ450F, complete with a red/gray/silver motif.

WHAT WAS IT LIKE TO RIDE?

Wiseco used a fine tooth comb when surveying the Yamaha YZ450F, making sure that every possible area in need of improvement was covered. Weisco decided to focus on three major areas: the engine, suspension, and controls.

(1) Engine: Wiseco was wise to select this bike for their project. The Yamaha YZ450F of the last two years (2008 and 2009) has a workmanlike engine that’s hindered by the over-engineered conical chamber muffler. In stock trim, the YZ450F is pleasant, but not omnipotent. But with the help of several internal modifications by Wiseco, the YZ450F was drastically improved over the stocker. Instead of a mellow hit on the bottom, the Wiseco YZ450F offered pep from the get-go. The engine pulled hard from the bottom through the middle, where the powerplant really came to life. Top-end power wasn’t sacrificed, meaning that the lackadaisical low-to-mid power of the stock YZ450F received a tremendous facelift thanks to the Wiseco internals. Of course, keeping the stock exhaust system on the bike would be comparable to slapping a Yugo bumper sticker on a Ferrari, so Wiseco installed a high-quality DR.D exhaust system to improve performance throughout the entire spread of the powerband. And, although not exactly engine related, the Wiseco complete clutch had a good smooth feeling with only minimal clutch lever fade over the course of a long moto. To sum up, the Wiseco YZ450F’s powerband suited nearly every skill level (save for top-end only riders).

(2) Suspension: Ever since Yamaha switched to Kayaba’s Speed Sensitive System suspension (SSS), MXA test riders have been enamored with its performance. Kayaba’s SSS suspension offers very good bottoming resistance and smooth actuation. Simply put, it’s the best stock suspension on the market. Pro Action understood our happiness and only made small refinements to the forks and shock. In the fork department, Pro Action utilized the same stock spring rates (0.47 kg/mm) and made clicker and valving changes. Considering that the suspension was set up for Intermediate to Pro-level riders, D.J. Korzen made sure that the forks could handle big hits at speed. Equally important was the fork action in small chop and through corners. The Pro Action modified units were plush in the smaller bumps and reacted smoothly in rutted corners with acceleration bumps.

Interestingly enough, Pro Action elected to go with a slightly softer shock spring (5.4 kg/mm) than the 5.5 kg/mm stocker. The shock sat up high in the stroke to improve the YZ450F’s lackluster turning, which did help the front-end bite in off-camber corners. Overall, the suspension did a very good job of handling a plethora of different size bumps, but it still needed the rear wheel to steer the bike through the corners.

(3) Controls: Wiseco opted for Braking’s 270mm front rotor and a Braking cauliflower rear rotor, which greatly improved the YZ450F’s pucker power. We were very pleased with the performance from the Braking rotors. The Renthal Twinwall Carmichael bend bars immediately felt comfortable, and a Renthal Intellilever ensured that there wouldn’t be any issues caused by a broken clutch lever.

Of all the aftermarket items on the bike, the product that test riders needed the most time to get used to was the Boyesen Shokout grip. The MXA wrecking crew recommends this product to those with weak or injured wrists (the Boyesen grip has elastomer bumpers that allow the clutch grip to absorb energy from hard landings), but not every test rider instantly adapted to the movement of the left grip.

VERDICT: WHAT DO WE THINK?

Kudos to Wiseco for taking the YZ450F’s mediocre powerband and spicing it up to racing standards. Best of all, they didn’t go overboard in the horsepower department. Test riders even stated that it was the best YZ450F engine that they have ridden in the past two years. We think that the Wiseco engine mods benefit nearly every classification of rider. If you fall into the category of being dissatisfied with the engine output of your 2008 or ’09 YZ450F, enlisting Wiseco’s services would be a wise choice.

For more information, contact Wiseco at (800) 321-1364 or visit www.wiseco.com.