ATP powers the TPR project YFZ450R

We are go for lift-off! ATP Racing Engines has completed the engine work for the TPR project YFZ450R motocross quad, and this engine rips!

We picked up the TPR project YFZ450R from ATP at this past weekend's Unadilla ATV motocross national, where several ATP riders were pulling holeshots and winning motos during the two-day event. ATP Racing Engines powers several winning riders who currently are in contention for championships in the ITP/Moose Racing AMA ATV Motocross nationals.

The engine mods for the TPR project YFZ450R started with multiple dyno runs for the stock quad. Straight from the factory, the new YFZ450R put 44 horspower to the rear wheels on the ATP dyno.

Mike Walker, the owner of ATP Racing Engines, said the initial dyno runs determined how the bike was modified.

“Once we’re pretty much in the ballpark and we see where the power’s going to end up, we’ll change the camshaft degree, we’ll change a lot of different things,” Walker said.

All great engines start with a good piston, and ATP installed a high-compression, 13.5:1 JE piston in the TPR project quad.

Next, ATP began to port and polish the head and modify the valve seats with the aid of a $50,000 Serdi flow machine.

"A Serdi machine is one of your upper level seat and guide machines," Walker said. "It’s where we pick up air flow, low-lift numbers. Most of your valve job work will improve your low-lift air flow numbers, which, will in turn translate to seat of the pants for a rider, better throttle response and initial hit, things of that nature."

The stock valves and springs were retained for the build.

Two aftermarket camshafts were used in the build. ATP starts with OEM camshafts from 2004-2005 model year YFZ450s and re-degrees the cams for more duration and lift. The re-degrees are based on extensive dyno testing.

ATP then installed our full Motoworks SR4 exhaust system, Motoworks FMI and Twin-Air Power Flow intake system before heading back to the dyno.

ATP produced an additional 8 horsepower from the TPR project YFZ450R without pushing the limits of the engine components. At 52 horsepower, our project 2009 Yamaha YFZ450R provides a tremendous amount of usable power.

Walker said the Motoworks SR4 exhaust and FMI tuner are easy to install and work with for the average rider or racer, yet they provide power capable of winning national races.

"The Motoworks tuner is a great tuner for your average guy," Walker said. "It’s very easy to install, very easy to work with. The pipe was a great installation on the bike and an easy fit."

To learn more about ATP Racing Engines products and modifications, check them out online at http://www.atpracingengines.com/

Thrilla' at Unadilla

The pro motos were close this weekend at the ITP/Moose Racing AMA ATV Motocross National at the Unadilla complex in New Berlin, N.Y., despite Monster Energy Kawasaki's Chad Wienen finishing 1-1 for the pro overall.

Baldwin Motorsports American Honda rider Josh Upperman pulled the holeshot in moto one and held on to the lead for several laps. He was followed by Rockstar/Makita Suzuki's Doug Gust and Wienen.

It didn't take long for Weinen to pass Gust in a corner at the far back of the track, but Upperman provided a greater challenge to the new series leader. Wienen shadowed Upperman for several laps before passing the Honda rider to take the win in moto one.

In moto two, Gust pulled the $250 MotorcycleUSA.com holeshot, but Wienen passed Gust by the time the field hit Unadilla's infamous Gravity Cavity on the first lap.

Can-Am/Warnert Racing's John Natalie quickly moved into third and pressured Gust for second for nearly the entire 22-minute moto.


Natalie got around Gust by diving to the inside of a turn leading to a challenging uphill double just three corners from the checkered flag. Natalie's last-second pass, combined with a fifth-place finish in moto one, earned him third overall for the weekend.

And Gust's 3-3 finish netted him second overall behind Wienen.

The story this weekend was the fate of defending champion Rockstar/Makita Suzuki rider Dustin Wimmer and his closest competition, American Honda backed Joe Byrd.

Both Byrd and Wimmer dealt with poor starts and finished mid-pack in the first pro moto. In the second moto, Byrd rolled off the track with a mechanical failure. Throughout the weekend, it sounded like the former champ was missing shifts in some of the corners. If I had to guess, Byrd may have struggled with transmission or clutch problems.

Wimmer rode stronger than he did in moto one and made several smooth passes around Upperman and Motoworks/Can-Am rider Jeremy Lawson to finish fourth in the second moto and take sixth overall. The defending champ lost his points lead to Byrd two rounds ago after dislocating his shoulder in practice, but both riders relinquished the top spot to Wienen after his dominating finish this weekend.

After seven rounds, Wienen now leads the battle for the 2009 ITP/Moose Racing ATV Motocross Championship with 254 points and two wins. Byrd hung on to second with 245 points, and Wimmer is close behind with 235 points as the battle heads to Muddy Creek in Tennessee June 27.

Maxxis - soft compound razr mx

As promised, here's the low down and some photos of the championship-winning Maxxis Razr MX motocross tires we'll be running on the TPR project YFZ450R.

Tire choice is absolutely critical and has more of an impact on performance and handling than most riders and novice racers are aware of. Tire size and pressure are just as crucial when it comes to tackling slick, blue-grooved hard pack or thick, damp and loamy motocross tracks.

The TPR project YFZ450R will compete in the Competition Riders of America series spread throughout the Ohio Valley, where the tracks are far-ranging between these two extreme soil types. To keep us competitive, Maxxis sent their soft-compound Razr MX tires in 18-inch rears and 19-inch fronts. Coupled with our DWT beadlock wheels, the TPR project YFZ450R is going to corner like its on rails.

As mentioned in an earlier post, we also have a set of Maxxis Razr MX medium-compound rear tires and Razr Cross fronts. The soft compound tires should give us extra grip on the hardpack, while the medium-compound Razrs and Razr Cross fronts should give the TPR YFZ450R an edge in the loam.

Maxxis offers several options for motocross and XC racing, so check them out here for your next set of kicks http://www.maxxis.com/MotorcycleATV/ATV-Sport.aspx

A picture says a thousand words

Look for a full post on the ATP Racing Engines build for the TPR project YFZ450R soon.

DWT makes TPR a champion in a box

At last! One of the most trick aspects of the TPR project Yamaha YFZ450R build has arrived. Douglas Wheel Technologies hooked us up with their Champion in a Box Alumilite Ultimate Race Kit.


The DWT Champion in a Box kit for the TPR project YFZ450R includes four pro-level, aluminum outer beadlock wheels. The kit includes all the mounting hardware for the rings, four mud plugs and a stylish DWT hat.

The rear G2 beadlock wheels are lighter than the DWT original Ultimate wheels. The rear wheels feature an improvement to the nut plate attachment and better fatigue resistance with their shot-peened wheel rings.

The RokOut front rims feature a mesh-like cut in the center of the aluminum rim to keep stones and track debris out of the rotor and other hub parts. The Universal Built-in Rock Guard — as DWT calls it — works with all stock front hubs and most aftermarket hubs. The guard stops outside debris from entering, preventing damage to brake lines, calipers and the wheel. The Rock Guard also eliminates the stock OEM steel rock guard plates for further convenience and weight reduction.

The Integral Rock Guard stiffens the wheel center, yet these wheels are also lighter than DWT's original Ultimate beadlock.

These wheels are incredibly light and super trick. We'll be running a set of four Maxxis Razr MX soft compound motocross tires to complement the DWT wheels on the project TPR 2009 Yamaha YFZ450R motocross quad.

Look for a post on the soft-compound Razr MX tires later this week.

We had been waiting on DWT to ship us wheels for the project because Douglas has been swamped with orders this year. They shipped the TPR set practically straight from the shop floor. The sheer number of orders DWT gets each year proves they are the king of ATV aftermarket wheels.

ATV Four Play

Like ATP, Motoworks, DWT and Maxxis, ATV Four Play is a primary sponsor of the TPR project Yamaha YFZ450R.

Four Play made a name for itself producing pro-level suspension components. In 2007, they helped John Natalie win the now-defunct WPSA title, and Four Play's a-arms appeared on the cover of Quad magazine with John. Naturally, Four Play is providing a set of its MGC long-travel MX a-arms for our build.

The newsy aspect of Tarantula Performance Racing's partnership with ATV Four Play has to do with their Gen II Soft Bars we'll be running on the TPR project motocross quad.

These bars had a big impact on the industry when they were released last year. A leading aftermarket bar manufacturer lodged a legal complaint saying Four Play copied its design. Riders and racers, however, supported the new (and drastically different) product and argued competition in the flexible handlebar market would be better for the customer.

The Gen II Soft Bars mount directly to aftermarket steering stems and will work with some stock steering stems, including the TPR Yamaha YFZ450R. These handlebars are specific to ATV use.

The bars are designed to reduce the severity of the shocks and impacts dealt to a rider's upper body while racing. The bars incorporate a Progressive Dampening System, which uses a dual rate vertical cartridge installed in the upright pivot assembly. This fully adjustable system allows for light resistance at the beginning of the travel to an increasingly heavier resistance at the end of travel.

Bottom line, you can ride harder for longer periods of time with these new bars. To learn more, check out http://www.atvfourplay.com/

Update - project status

Here's a quick update on the status of the TPR project 2009 Yamaha YFZ450R motocross build.

Currently the TPR YFZ450R is at ATP Racing Engines' shop in Florida where Mike probably has his hands in the top end as you read this. The engine work will be finished in time for us to meet up with ATP at the Unadilla MX national June 13.

After we get the quad back from ATP, the next steps will be for ATV Four Play to finish building our MGC long-travel MX a-arms and TPR to build the Race Safe bumper and nerfs.

Then it's a matter of installing all the performance parts we've been posting about here in the past few weeks and meeting up with ATVOnDemand.com to have a pro-am rider put in some laps and give us feedback on the quad's performance.

We're still working out the details with a graphics kit, but a tentative completion date for the project, if all goes well, is by the end of June.