Yamaha Motorcycle tests
Here’s a hypothetical situation. Pretend you’re an offroad racing champion (perhaps you’re the WORCS champion, Endurocross title holder and have won ISDE medals). You’ve been so successful that you are paid a handsome salary, are feted in the press and have a full-boat ride. Now, imagine that your real passion is motocross.
The conundrum is that no one wants to pay you to race motocross, but they will pay you to keep racing offroad races. When you ask your factory sponsors if you could switch to motocross, they tell you that you don’t have any experience. So, to prove to them that you can do the job, you go out and finish sixth overall at the 2009 Red Bud 450 National. Will they sign you to race motocross for them? No, but they offer you even more money to sign a long-term offroad racing contract. Do you take the money and forget your dream? If you’re Ricky Dietrich, you walk away.
Is Dietrich a few bolts short of a full bike? It depends on what you value in life. In an economy as weak as an anorexic runway model, most people would take the safe bet and pad their bank account for the future. Not Ricky Dietrich. He quit his Factory Kawasaki offroad ride and became a full-time motocrosser.
The MXA wrecking crew has nothing but praise for Dietrich’s bold—if a bit insane—decision. Ricky opened our eyes to his promise as a motocross racer two years ago as a fill-in for the injured Ryan Villopoto on the Monster Energy Kawasaki factory team. We knew then that it was only a matter of time before Dietrich pursued a career in motocross.
Valli Motorsports claims that Dietrich’s Yamaha YZ450F is a “catalog
bike.” They aren’t lying. Almost all of the parts on Ricky’s racer are
Ricky couldn’t get Kawasaki to help him fulfill his motocross ambitions, but the Valli Motorsports team stepped up and signed Dietrich to a 13-race deal. (That isn’t a typo.) Why 13 races when the 450 Nationals are only 12 races long? Ricky raced the Daytona Supercross and Then the 12-round National series. In a time when race teams put a greater emphasis on Supercross than motocross, Valli Motorsports owner Chad Lanza offered Ricky an outdoor-only deal. Why? What Ricky lacks in Supercross (and National) experience, he more than makes up for with drive, determination and a willingness to learn. Lanza also knew that Dietrich’s endurance wouldn’t be a problem (Ricky can do hour-long motos in his sleep, thanks to the length of offroad events).
Valli Motorsports needed Ricky Dietrich just as much as Ricky needed Valli. One of their team riders, Austin Stroupe, had been hampered with lingering injuries all season long. The Valli Motorsports/Ricky Dietrich pairing was a stroke of genius, because most people forget that Valli Motorsports started as an offroad team well before they entered the motocross circus. Lanza and Dietrich share the same racing roots; it’s only logical that Valli would sign Ricky for the 2011 Lucas Oil AMA 450 Nationals.
The MXA wrecking crew has dabbled in offroad racing (racing WORCS, Endurocross and GNCC events when we have the time), and we know how tough it is, so we were chomping at the bit to ride Ricky Dietrich’s Valli Yamaha YZ450F.
SHOP TALK: DISSECTING THE RACE WEAPON
Valli Motorsports is one of a handful of factory-backed Yamaha teams on the circuit. Valli has access to works Yamaha components that are unavailable to the public. They are in no way a privateer team, but we were surprised to discover that Ricky Dietrich’s bike isn’t littered with factory trinkets. Aside from a few items, Dietrich’s Valli Motorsports Yamaha YZ450F is a bike that a local racer could build to Ricky’s exact specifications. The Valli team prides themselves on racing what they jokingly call a “catalog bike.” Don’t let the comical description of Ricky’s steed fool you. The Valli Motorsports YZ450F is on par with other top-tier bikes on the National circuit, and for good reason. Chad Lanza spares no expense in outfitting his riders with the best equipment available. It’s true that Ricky Dietrich’s bike could be duplicated by the average Joe, but it would cost a pretty penny.
GYTR supplies the camshafts, piston, porting modifications and cylinder head. This engine pumps out serious ponies.
The MXA wrecking crew can vouch for the GYTR-spec engine (we had GYTR build us a full-blown YZ450F engine for the May 2011 issue). GYTR is Yamaha’s in-house development company, and they know how to build a fire-breathing engine. Dietrich’s powerplant has a GYTR cylinder head (with porting done by a five-axis CNC machine for a precise job that is the same every time), camshafts and high-compression piston (with a single ring for less friction). The valve train (valves, seats and retainers) is stock. To complement the engine, Valli uses a Pro Circuit Ti-4R race exhaust. The muffler has been shortened to improve bottom-end response.
Complementing the hard parts in the YZ450F engine is a
Vortex ignition. Valli has developed two custom maps that are programmed into the ignition. The first setting, used for starting, is more aggressive. The second setting, used during the race and changed by the flip of a handlebar-mounted switch, provides a more consistent throttle feel. Both settings reduce engine braking.
The four parts on Dietrich’s bike that aren’t for sale are the clutch springs (which are stiffer), rising-rate shock linkage, bell crank and close-ratio five-speed transmission. The tranny has different gear ratios, with a taller first gear and closer ratios between second, third and fourth. Tightening up the gaps between these gears promotes more precise shifting. First gear is used off the gate at the Lakewood, Colorado, National only (because of its high-elevation and uphill start).
In an effort to efficiently flow more coolant, a Boyesen water pump cover with an oversized impeller is used. Also helping the cooling system are Faction radiator Y-kit hoses. And, like most teams on the professional circuit, Valli uses a self-siphoning radiator catch tank that is made by the team. A 1.8 kg/cm radiator cap prevents the coolant from boiling over. Pro Circuit lines the bottom of the gas tank with heat tape to act as a barrier between the hot engine/exhaust and VP Pro-5 race fuel.
Valli Motorsports and Pro Circuit have developed a close relationship since the team entered the motocross ring in 2010. It also doesn’t hurt that John Mitcheff, team manager at Valli, used to spin wrenches on the Pro Circuit race team. With an open line of communication (not to mention deep pockets on Lanza’s part), the two parties work closely together.
The best way to ride Dietrich’s bike was to sit directly over the
shock and steer with the throttle. It took some getting used to. All of
the test riders agreed that the Valli bike was a rocket ship. Need
evidence? Take a look at this blown-up berm.
Valli Motorsports uses Pro Circuit Showa A-kit suspension, though the
valving, testing and servicing is done in-house at Valli by Todd Brown.
For years, Brown worked at Factory Connection before moving over to
Valli. He knows his stuff when it comes to setting up suspensionUp front, the 49mm forks come with stiffer springs and different valving. Housing the Showa forks are Pro Circuit triple clamps with the stock offset. The clamps have 8mm-taller bar mounts and are positioned 5mm back from the center with 4mm cones. The real area of interest is the Showa A-kit shock. What’s so unique about the shock is the works Yamaha B1 bell crank at the base of the shock. Not for sale, the B1 (B1 is simply a model name) gives the shock a more aggressive feel in the initial part of the stroke. It does this by changing the angle of the shock, and, instead of the rear wheel driving up after hitting a bump, it drives the rear wheel into the shock to prevent the rear end from hopping. The B1 bell crank is primarily used for Supercross, but Dietrich took an immediate liking to the feel of the shock during testing. A 1mm internal spacer was installed to shorten the shock and keep the rising rate firm in the initial part of the stroke. To complement the shock, Ricky uses a 3mm-longer (145mm) pull rod that works in conjunction with the shock bell crank to lower the rear and change the compression damping. The pull rod is a works Yamaha part (referred to as OW spec). As for the subframe, it has been lowered to prevent the seat from hitting Ricky’s rear end.
The Valli Motorsports team insists that their bikes can essentially be purchased from a catalog, and that 95 percent of the components on Dietrich’s YZ450F are for sale. They aren’t lying. A host of aftermarket companies are instrumental in getting Ricky’s bike to the starting line. Here is a list: DT-1 air filter (with an aluminum cage); Braking Batfly oversized front rotor and standard rear rotor; GYTR clutch cover; Talon hub; Excel A-60 rims; GYTR sprockets (49-tooth rear); Cycra front number plate (which extends below the lower triple clamps to protect the aluminum from roost) and one-piece radiator shrouds; N-Style graphics and high-traction seat cover; Pro Taper grips; Pro Taper Ricky Carmichael high-bend handlebars; Pro Taper aluminum throttle tube; Eko full-titanium bolt kit; ARC clutch lever; LightSpeed carbon fiber parts (skid plate, front brake guard, rear caliper guard, footpegs and chain guide); Hammerhead shifter, rear brake pedal and starting button; Dunlop MX51 front tire mated with a 762 prototype rear tire; and team sponsors’ decals (which include Rockstar Energy Drink and GoPro cameras).
TEST RIDE: FEELING IT OUT
Let’s preface this test by stating that Ricky Dietrich’s Valli Motorsports Yamaha YZ450F was interesting before we even rode the bike around a track. Dietrich’s mechanic, Eddie Laret, mentioned that Ricky’s setup was more aligned with offroad racing than motocross. The 5-foot-9 rider has a drastically different shock, shortened subframe, tall bar mounts with extraordinarily low-sweeping handlebars, a clutch lever that’s higher than the brake lever (the higher clutch lever forces Ricky to keep his left shoulder up) and a rear brake pedal that almost touches the moon. It was no secret that test riders would have difficulty coming to terms with Dietrich’s unique setup.
For starters, Ricky Dietrich turns the YZ450F with the throttle. How do we know? Even riding down pit road the bike was severely out of balance. Several testers likened it to riding a Harley-Davidson. The rear of the bike sat low, while the handlebars were nearly in line with our armpits. The out-of-whack balance was reminiscent of another Ricky we know: Ricky Carmichael. RC was famous for his dead-feeling shock and weird bar/peg/seat relationship. We may not like either Ricky’s setup, but it is obvious that it works for them. But, it is completely opposite of what most motocross riders prefer, which is a balanced bike with most of the load on the front end through corners. Needless to say, it took testers a great deal of time to figure out the balancing act necessary to ride Dietrich’s bike.
Ricky has access to two ignition profiles while racing—a start map and race setting. We preferred the start map.
Some testers complained that the front tire was flat, but a quick glance down showed a full Dunlop MX51. It was only when these same riders moved back on the seat and loaded the shock that the front end felt more consistent. The technique of most riders is to move forward on the seat and weight the front end when entering a turn, but the opposite was necessary to negotiate a corner effectively on Ricky’s bike. We learned to lean back while standing up on bumpy straights and stay back when it came time to sit down. Ricky Dietrich rarely wears out his front tire, while his Valli teammate, Nick Wey, goes through them like water.
Ricky’s Valli Motorsports YZ450F isn’t for the faint of heart or those short on skill. Only a Pro-level rider could appreciate the quirks of this bike, its suspension performance, the gobs of horsepower that growl from the engine and the works transmission. As Eddie Laret said, “Don’t even bother trying to ride Ricky’s bike unless you’re giving it 110 percent.” He was right. However, in order to find a modicum of comfort, we lowered the very high rear brake pedal, which we stepped on at the worst possible moments (such as when landing from jumps and powering out of corners). This minor change helped riders feel more confident on the bike, which encouraged them to give it their all.
The GYTR engine wasn’t dissimilar to the powerplant we raced several months ago, and we weren’t surprised. What’s so special about the GYTR powerplant, other than the company’s never-ending search for improving performance, is that the computer technology that GYTR uses guarantees identical results. The GYTR Yamaha YZ450F engine is a low-altitude rocket ship. That’s peace of mind. Where Dietrich’s engine performance differed from our GYTR race engine was when we switched back and forth between the two custom ignition settings. We preferred to use the start setting all the time. As for Ricky, he does the exact same thing—rarely switching the map over to the race setting.
CONCLUSION: WHAT DO WE REALLY THINK?
We applaud Ricky Dietrich for stepping out of his comfort zone to pursue motocross stardom. It was a leap of faith, but the gamble just might pay off. He has the ability to be a top-ten 450 National rider, but had trouble sin the second half of the AMA 450 Nationals. We commend Valli Motorsports for recognizing Dietrich’s talent and offering the offroad ace a ride. For the two parties, it was a match made in heaven. Bravo!