What is the Magical Mystery Concoction to spawn a Champion? Is it more bike and less rider, or is it mostly rider and partial the bike? SMR aspired to get some answers and we went straight to the source - the two number one plated machines. In 2007, the right to claim Excellency and Supremacy came in the form of two AMA championships that made their way into the hands of two talented riders and a fanatical team dedicated to the art of building winning machinery. Of course we're speaking of Mark Burkhart, Brandon Currie and Graves Motorsports.
Graves Motorsports is the name behind Yamaha's factory-backed supermoto team and the proprietor of two championship plates. Most of you who follow the sport are well aware that Graves is far from a team that simply services the Yamaha Factory machines. They build and develop their race bikes from the ground up. Yes, Yamaha supplies and helps tune Mark Burkhart’s factory suspension and offers input, but from there it's all Graves, all the time. What's unique about this factory backed effort is the fact that a good majority of the parts developed by Graves are manufactured by and available from Graves Motorsports. Another key component that significantly contributes to the success of the Graves Team is their habitual nature of staying a step ahead with regard to development. Burkhart's and Currie's race bikes were no exception.
While catching glimpses of theses two marvels all year long under the Graves' semi tent, we wanted to get a taste, or at least a nibble of what victory tastes like. Burkhart's mount at the final two rounds of the '07 series was actually an '08 YZ450F. Brandon Currie's champ bike was based off the '07 chassis. For our test day BC's ride retained the same setup he used during the final two rounds to sew up the title. Loaded with this data, we aimed to solve the questions posted in the first sentence above.
TECHNOLOGY
Although we poked, prodded, cajoled and even begged, the Graves' camp is pretty tight-lipped when it comes to the exact technology locked inside their race bikes. Some of our ranting may be speculative with regard to what makes these bikes so competitive, so please bear with us. The engine is the life blood of the team's effort. We asked if the average gut could get an exact copy of Burkhart's engine. Although Graves sells most of the components on their build list, acquiring an exact replica might be another story. After asking, the Graves guys joked around and said that anything is possible with the right offer. There’s truth to the fact that all of the components available to the public were first developed for the teams race bikes. So in a sense, you're getting the Burkhart or Currie race bike technology.
We do know that Graves goes the extra mile when it comes to performing cylinder head modifications. We've heard that all of the cylinders are ported not by hand but rather by using a CNC computer controlled mill. Once they dial in the porting, the numbers are programmed into a computer and each head from there is an exact copy of the previous one. The program can also be altered for a design grind.
While the head work is being fine-tuned during development, the same treatment and extensive testing goes into the cams, valves, pistons and valve springs. This combo along with the ignition and carb settings is what creates the magic on the track.
One of the coolest discoveries during our test day had to do with the programmable ignition. We always noticed two kill buttons on the handlebar of both 250 and 450 race bikes and just figured that one was to switch ignition curves on the fly. We couldn't have been more wrong. As it turns out, the second switch, located just to the right of the left grip, is an ignition interruption switch, so the rider can speed shift the bike without having to touch the clutch or blip the throttle. As the rider grabs the next gear, they tap the little red buuton with their thumb and the bike easily up shifts into the next one. Even if you hold the button down it only cuts the ignition for a millisecond. And, the duration of the interruption can be programmed into the box. This feature isn’t proprietary to the race team, its available to the public. All Graves' ignitions for the YZ250F and YZ450F are capable of being set up with a quick shift ignition switch.
As for the rest of the engine, the transmission. the crank and the other components, they've been massaged in some way, shape or form. The clutch is claimed to be GYTR but we speculate there's some sort of slipper clutch, possibly a Works Yamaha part. The last time we checked, the Yamaha GYTR catalog doesn’t offer a slipper clutch but they do sell clutch baskets.
CHASSIS
Fast is awesome but eventually the bike has to turn as well. Graves doesn't hold back in this department either. Because of the AMA rules that require stock upper and lower tubes, lower lugs and no special coatings, Currie's YZ250F runs production suspension. Although stock on the outside, the internals are tuned and valved. As for Burkhart’s ride, he gets the platinum treatment and has the choice to run Works Kayaba suspension. The Works forks runs 50mm lower tubes compared to the smaller stock units.
From there the team conducts hours of testing with much of the testing going into chassis tuning. Especially in the areas of triple clamp offset and linkage curves and heights. If anyone has done any testing aboard a supermoto bike, you know that even a millimeter adjustment to the chassis can, and will change the handling of the machine. With their years of experience in road racing, Graves knows chassis setup.
TRICK PARTS
As we started to look closer at the Graves' machines, we could see the niceties that bring together these awesome creatures. Everything from the hand crafted catch cans and oil breather boxes, CNC-machined chain guides and buffers and the locking axle blocks exemplify the team's effort it takes to build bikes of this caliber. Even the brakes go the extra mile. Yes, most of the parts are off-the-shelf components but Graves even them to maximize performance. We've used the same master caliper and rotor combination on project bikes but we've never been able to get them to work even close to the Graves' machines. Tuning with pads, brake lines, fluid and levers must make a difference.
REGULAR SUSPECTS
The rest of the parts on the race bikes are made up of widely used components such as the wheels, Dunlop tires, Cycra plastic, K&N air filters, DID chains, Lightspeed guards, Pro Taper bars and AFAM sprockets.
SPEECHLESS
"Oh my gosh, is that bike fast or what?" This is an example of the type of sentiments that were uttered from our test staff. Cameron Welsh pulled off the track after the first lap to shake Graves' engine builder Jerry Daggets hand for building such an awesome machine. We're talking about Burkhart’s 450. We've ridden some fast 450s in our time, but WOW! We even rode Doug Henry's bike two years ago but this 450 is nothing like the bike of the past. The '05 bike team bike was fast with a smooth delivery but compared to the champ's bike, the '05 race bike was tame on the bottom and didn’t have a rush in the mid.
The biggest disappointment was the fact that we couldn't take the bike home or get a chance to race a local event on it. The bike is flat out fast with sick amounts of useable bottom and a mid-to-top end rush that's second to none. It had been a few years since we've had a chance to ride a championship bike from a major team. Things have come a long way. If the older team bikes made 60 horsepower, this bike must be making 65. It's amazing how much better the bikes have gotten in two years.
Fast? Yes, but the strange thing is that the power, coupled with the awesome chassis, keeps the tires planted on any part of the track. We've ridden 610 cc KTMs that go millions but found that they can be a handful to ride. This isn't the case with the Graves bike. We thought the CRF450R project bike we raced for most of the year was a runner until we threw a leg over Burkhart’s machine. And to back up the engine, the chassis was equally as remarkable. Whether it be braking, turning or dropping into the corners-the bike is just sick.
Currie's 250 is equally impressive in the motor department and it was apparent all year during his battles with Troy Lee Designs CRF of David Pingree. It was as if Currie's and Ping's bikes were in a class of their own. They could often overpower any other 250 in the track. After a day on Currie's bike. Welsh looked over at his partially modified 250F and a small tear started to roll down his cheek.
MAN OR MACHINE
After it's all said and done, did you think we'd rag on the champs' bikes and claimed that they handled poorly or were slow? I think not. After spending a day on bikes of this caliber, you can’t stop thinking that there's an advantage here. But in the end a chump on a factory bike can't necessarily win a championship and guys like Burkhart or Currie probably wouldn’t be champs if they had to ride stock machines with just wheels and brakes. So, the answer to the question in the first paragraph-Man needs the machine and the machine needs the man.
SMR
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