Thursday 23 January 2014

2012 Honda CBR250R Project Bike

Motorcycle road racing always has, and always will be expensive. But considering the price tag of Honda’s 2012 CBR250R ($4099) the cost to compete and taste the thrill of riding in close formation, bar-to-bar, knee sliding across pavement is dramatically reduced… or is it? We aimed to find out so we went racing.

FROM STREET BIKE TO RACEBIKE

One of the biggest advantages of 250cc racing is how much simpler it is to convert into a racer. Still, having barely enough mechanical aptitude to pass high school shop class, we preferred to leave the wrench turning to the pros: enter Jett Tuning. Owned by long-time mechanic and former factory American Honda tuner, John Ethell, his Camarillo, California-based workshop is a worthwhile choice for all your mechanical needs. He’s thorough, quick, and charges a reasonable rate of $100/hour.

The first order of business was to peel off the street bodywork and replace it with a  Hotbodies Racing Race Bodyworks Full Set paired to a windscreen from Zero Gravity. While it is possible to race with the stock plastic, (as long as you remove the mirrors and lighting equipment) why take the risk of banging it up, especially if you plan on riding again on the street. We purchased Hotbodies because it was one of the only manufacturers to actually have the parts in stock, plus it costs less than $600 for the set including shipping. While the quality isn’t as high as other, more expensive brands we’ve used, based on the price, it’s a deal that’s hard to pass up.

With the bike naked, we tossed out the heavy and restrictive stock exhaust and sourced one from Yoshimura. Although it isn’t the cheapest pipe in the aftermarket world, we’ve yet to find an exhaust that offers as much value in terms of price, performance, and build-quality. We also refined the drivetrain by fitting a pair of sprockets from Driven spun by a stronger DID ER2 chain.


It’s all about optimum line selection and holding the throttle on as long as possible when you’re 250cc four-stroke racing.

Because the CBR is fuel-injected, the engine will still run adequately in spite of the added exhaust flow. But since we were aiming to maximize engine performance we fitted a Dynojet Power Commander V with optional Dynojet Quick Shifter Expansion Module (allows for lightning fast transmission upshifts.) The Power Commander allows the engine tuner to alter the fuel-injection and ignition timing maps in an effort to improve acceleration power but make the bike’s powerband smoother and easier to manage, too. While Dynojet has gone the extra mile to develop easy-to-use software, for optimum results you still need access to a motorcycle dynamometer and someone who really understands the subtle nuances of engine tuning. This is where Ethell’s decades of racing experience come into play.

Next up was the chassis. While the little CBR’s suspension works great when you’re commuting to work, at an elevated pace it’s more forgiving damping settings will quickly be overwhelmed. The answer is to replace the stock shock absorber for one from Ohlins. Up front, we poured in heavier-weight fork oil and preload adjuster fork caps that allow for some degree of front suspension tuning based on rider weight.

Brakes are an area in which you should never skimp. So we fitted a wave-style rotor from Galfer with a matching set of stronger biting brake pads in addition to a  Galfer Colored Sport Bike Brake Lines kit. Lastly, a pair of Renthal Road Race Full Diamond Grips was installed and we purchased a GPS-enabled Solo lap timing device from AIM.

Tires are the final pieces of the puzzle, so we mounted a set from Pirelli. Up front we ran a full-race SC1 compound Pirelli Diablo Supercorsa (110/70-17) and  Pirelli Diablo Rosso II Rear Tire (140/70-17). Keen track day riders and racers might wonder why we ran a Rossi II street tire as opposed to the Supercorsa. The reason is the Supercorsa offers a shorter aspect ratio (60 vs. 70) which makes the rear end of the motorcycle sit lower thereby reducing steering response. And while it may offer a hair more grip it can’t match the street tire’s durability, allowing you to complete multiple race weekends on just one set of tires.

RACING SIMPLIFIED

Originally I was planning on saving my 250 racing experience for a later date, but circumstance led to the bike being available to race on Sunday during Round 8 of the WERA West club racing series at Las Vegas Motor Speedway. Not wanting the bike to gather dust under the EZ-UP, I slipped on my suit and went for it.

Honda’s CBR250R proves you don’t need to spend a lot of money to be entertained on the racing track.

Arriving at the track on race day always presents a unique set of challenges, the main one being bike set-up and actual practice time. Due to the little CBR’s simplicity set-up is limited to checking tire pressure, setting the height of the brake and clutch lever and topping off the gas tank with U4.4 from VP Racing Fuels. Set-up done, check.

When racing with WERA, each class gets two short practice sessions then it’s time to race. Typically that minimal amount of seat time makes it difficult to get up to speed if you’re riding a larger, more powerful motorcycle. But since I was on a 250, two 10-minute practices would be plenty… or so I thought.

Compared to larger, 120-horsepower 600cc sportbike which demands some degree of throttle hand restraint, on a 250, the name of the game is all throttle, all the time. The biggest challenge is how long you can keep the throttle pinned before flicking it into the corner, while using the least amount of braking force as possible.

When you have just 30 horsepower at the back tire everything on track happens at a more quantitative mental pace. The bend ahead arrives a little later and racing within inches of the guy next to you doesn’t seem as risky. Since you don’t have the torque and acceleration power of a big bike, you can’t throttle your way out of mistakes which makes maintaining forward momentum the most critical aspect of the ride. Not only does it force you to follow the optimum racing line, it teaches you to keep every mph of speed you’ve got. It’s these reasons that make 250 racing great for those new to the sport or someone looking for a refresher course in racing.

While proper line choice comes easily, exploring the limits of tire adhesion proves to be more demanding. Based on our bike’s approximate 325-pound curb weight, not to

Riding or racing a Honda CBR250R is a great way to experience the excitement of racing in a safer way.
mention the crazy grip available from the Pirelli rubber, it was a tougher time to acclimate to how much lean angle you could carry through corners as well as how hard you could load the front tire. It also took time to get comfortable riding through corners with the throttle pinned while upshifting into the next gear while your knee puck glides across the road. It’s a surreal experience and enough to make even a more experienced motorcyclist giddy with excitement.

In the next episode of our itty bitty CBR250R project racer adventure we visit Southern California’s Chuckwalla Valley Raceway and mix it up with a 40-plus pack of pesky green Ninjas to see if the little CBR that could can mix it up with its green nemesis.

No comments:

Post a Comment