WSB Honda CBR1000RR For The Street

Although Honda's new CBR1000RR appears to be coming off second best to its Japanese rivals in many of the inevitable magazine literbike shootouts, that's not the way it's turning out on the racetrack, thanks to two-time World Supersport champions Ten Kate Racing and its single Honda World Superbike entry. Built completely by the Dutch team's shop in Holland and ridden by reigning World Supersport champ Chris Vermeulen, the Ten Kate Honda CBR1000RR scored the first win by a 1000cc four-cylinder in World Superbike at the Silverstone, England, round. Considering that 49-year-old Dutch tuning guru Gerrit ten Kate and his nephew, Ronald (who, as his partner in the ultramodern Ten Kate Motoren Honda dealership at Nieuwleusen, Holland, near Assen, is also Ten Kate Racing's team manager), have had to develop the racing CBR from scratch themselves using a modified roadbike rather than one of the factory machines used for National-level competition by American Honda and Honda Britain, Vermeulen's performances this year on a bike that didn't exist eight weeks before the season's start have been pretty impressive.

I was invited to join the Ten Kate Honda team at the historic Assen circuit to ride a street-legal replica of Vermeulen's superbike, complete with a 180-horsepower motor and suspension identical to that used on the racebike. This CBR, carrying the trademark yellow-and-black livery of the Ten Kate Honda team and the "Ten Kate Edition" moniker, is available for approximately $30,500, including a pair of paddock stands and four different countershaft and rear sprockets to alter final gearing. Ten Kate will also offer an optional track-day bodywork kit for those who don't want to risk damaging the bike's street equipment on the racetrack.

"We've done quite a lot of work to produce this performance, but the CBR is so good in standard form, it's a great basis for tuning up to this level and beyond," says Gerrit ten Kate. "We have 203 horsepower at the rear wheel from our Superbike racer, with more to come, yet it's been really bulletproof. So 179.9 horsepower [read by a Dynojet dyno] is no trouble. But we don't lose anything in the bottom--it's still a very ridable bike." To achieve this substantial improvement over the stock CBR's 153 horsepower, Ten Kate Racing strips apart and blueprints the engine, retaining the stock gearbox, clutch, crank, con-rods and pistons. Then the team ports and flowbenches the cylinder head before fitting Ten Kate's own camshafts, identical to those used on Vermeulen's World Superbike racer. "We keep the same lift as stock, but we vary duration and valve timing a lot," says ten Kate. "Using a higher lift is what kills mileage, and though it's easy to get more power, we don't want to sacrifice reliability. That's why we only raise the compression a little from stock [from 11.9:1 to 12.7:1] by skimming the head."

Single racing springs are fitted to upgraded valves, which are reshaped and flat-faced, but still the same diameter and material as stock. A specially developed Arrow racing exhaust system utilizing stainless steel headers together with a titanium collector and silencer handles exhaust gases.

Interestingly, the Ten Kate team hasn't adopted HRC's racing-kit ECU for the PGM-EFI fuel injection system, nor has it been given the access codes to remap the stock engine management system. Instead, the Ten Kate Honda is fitted with a Dynojet Power Commander to optimize fueling; but ten Kate admits this is only a short-term solution. "This is fine for the street rider and for track days, too, which for sure will be what most people will use the bike for," he says. "But we know that some of our customers will want to go racing with this bike, and it should be very competitive as a privateer superbike if they do so. So for these people we're planning to [offer] our own ECU that will be fully programmable and will also allow you to raise the rev limiter, which you can't do at present. The power on the Ten Kate Edition is still building when it cuts out the engine, so a higher limiter would make what is already a very fast bike even faster!"

The stock CBR's aluminum twin-spar chassis and swingarm are left stock, with a racing WP shock (equipped with a hydraulic preload adjuster and both low- and high-speed compression and rebound adjustment) in place of the stock damper. Both the shock and the fully adjustable 50mm inverted fork are the creation of WP's Italian licensee, Andreani, with triple clamps machined from billet ergal aircraft alloy, and TIN-coated fork tubes to reduce friction. "Geometry is the same as our superbike racer," says ten Kate, "and we have our own shock dyno which we use to set up the suspension to exactly the same settings and ride height as the superbike." The riding position is identical to Vermeulen's racebike thanks to clip-ons mounted farther forward to compensate for the higher location of the Valtermoto footrest hangers, with the gear linkage pivoting around the left footrest for more precise shifts; there's a taller mounting for the matte-black single seat, which is ducted to help cool the underseat titanium exhaust can.

I was surprised at how civilized the Ten Kate Honda was in street riding conditions, content to putter along in traffic barely off-idle, with a light clutch action and a smooth, easy pickup from low revs. Once on an open highway or racetrack, however, the Ten Kate CBR will quickly shed its sheep's clothing to reveal a monstrous wolf that will gobble up most anything in its path. The impressive thing about the Ten Kate Edition CBR1000RR is its power wheelies through the gears exiting the Assen chicane, catapulting with unbelievable speed over the start line and through the fast kink leading up to the first turn. I'm quite certain that the Ten Kate Edition CBR1000RR is the fastest and most powerful motorcycle I've ridden around Assen, license plate or none.

You'd better make sure you have the Honda fairly upright before you pull the trigger, however, because even though the bike is very tractable at lower revs, once the power comes on at 6500 rpm the incredibly strong midrange torque can spin the rear tire and put a ham-fisted rider on his head in an instant. The Honda's performance is seriously addictive; you can't wait to get it up and gas it hard again along the next straight, ready to have the orange shifter light flashing in your eyes at 11,500 rpm. The surge of power lasts all the way to the 12,000-rpm rev limiter, the Honda still pulling hard as it shuts down the party.

The Ten Kate Edition isn't exactly nimble, but it does steer well, though you do have to work a little to make it change direction reasonably fast. The Andreani suspension works nicely on a track that is arguably the greatest test of a suspension package anywhere in the world due to the Assen circuit's high speeds and numerous camber changes. The multifaceted turns eat up a substantial amount of suspension travel through both camber-induced compression and midcorner bumps, yet the suspension package worked brilliantly, providing excellent feedback in every cornering situation I encountered.

An important element in helping the 383-pound racebike change direction well is the pair of 310mm Braking "margarita" petal discs that come standard on the Ten Kate Honda, and are identical to Vermeulen's racebike (matched to a 220mm rear that he hardly ever uses). Gripped by the stock four-pot Tokico radial calipers fitted with SBS carbon pads and steel brake lines, the wave discs help speed up the steering via reduced gyroscopic effect. This isn't imaginary, because I've proved it for myself against the stopwatch in a same-day comparo with conventional discs.

What's also impressive is the CBR's stability under hard braking; where some bikes tend to "back into" the turns, the Honda just slowed very hard without a lot of excessive weight transfer so that trailbraking into turns was no problem. This is in spite of the fact that you're sitting noticeably taller on the bike than on a stock CBR, with more body weight supported by your arms. The only things I felt the bike lacked were a powershifter and a slipper clutch (if Ten Kate ever gets the one it's experimenting with on Vermeulen's racebike to stop slipping under all that power, and work properly!); the rear wheel can chatter under engine braking for slower turns. It's also worth noting that the bike isn't easy to get off the line hard if you make a pretend start, as I did a couple of times.

The Ten Kate Edition CBR1000RR takes the Honda's performance to another level, removing the slightly oversanitized feel of the stock streetbike and adding World Superbike-developed zest and allure to create what by any standards must be the ultimate track-day tool, as well as a definite license-loser for those brave (foolhardy?) enough to exploit even a portion of its outrageous performance. Superbike racing has come full circle, and what we're now seeing is the resurgence of the tuners and specialist engineers capable of taking a volume production motorcycle and extracting untold performance from it for use on the racetrack in pursuit of victory--but then also delivering a very similar level of performance to customers to either race themselves or just have fun with. -SR