Cycle News - Archive Issues - 2000's

other customers. The chance to test-.ide the controversial and innovative Buell XB-RR when they plug the porrable $arter into the right side of the motor, and crank the Buell to life. There's somethinS very improbable about a bike thar looks like a 250cc GP racer Ehrobbing into action with a deep rumble from the exrt pipe on the left of the bellypan ,ust in front of the rear wheel. ln fact, the XB-RR is prerty quiet by the standards of this kind of race enSine, a tribute to the effective- ness of that long silencer that runs benearh the motor, even if rhe fact that it's still made in stainless steel means there's an instant 22-pound weight saving to be gained when the exhaust system rs madc in titanium. "Honestly, we're iust at the start of the whole project,' explains XB-RR Proje.t leader Steve Anderson. "We only be8an work on the bike last August, with the plan to be on the Srid for Da)tona in l''larch, build the llrst 50 bikes or so, and then work continuously on development, which we can pa5s on down to customers via altermarket pans. A ti-exhaust will be one of these, and should give us qurte a Sood iniection of added acceleration thanks to the wei8ht saving.'' Af(er grabbing first gear (the bikes come wrrh race-panern shifting) and taking to the track, I was suddenly aware that, for all the baret muted sound of thunder coming at me from within the fairing, there weren't any tingles making their way to the handlebars or footrests. Buell's trademark Uniplanar rubber mountings do a grear iob of removing all trace of undue vibration - the narrow-angle XB-RR motor shakes no worse than a 90-degree Ducati V-twin, in spite of the absence of a counterbalancer. lapment passed on to reinventing the race bike - the American ln the flesh, the XB-RR looks fairly meary as well as veD/ distinctive, albeit rarher short, broad and tall. That impres- sion is not borne out by sitting on it, rhouSh. for ir has a carefully tailored riding position thar delivers ample space for a 6- foot rider to tuck aboard the bike's not excessively high 775mm seat height and feel a part of the bike, rather than perched on top of it. Yo{r're not restricted at all from moving around on the Buell and hanging off it, in spite of the short I 34lmm wheelbase. lt feels close-fitting bu( not cramped, and quite aerodynamic at full tuck, with the fairinB s broad nose ductrng airflow past your shoulders, even though you must wrap your forearms round the twin variable-section carbon-fiber tubes running backward to the airbox from the single.entral intake duct in the nose of the bike. Unlike the Bimota S88. from which this layour is derived, it's not at all intrusive, and you don't notice it on the go. You can hunker your helmet down betlveen the ducts, though yor.t do getthe feeling its chin bar is about to make friends with the front fender - even with the thick seat Pad removed that .Jeremy uses to lever his body weight upward to throw more ol a load onto the front Pirelli. Without it. the wind-tunnel-developed X8-RR feels quite balanced and snug. AlthouEh it feels like a little 250cc GP racer when you sit on it, that changes these two bikes was a good chance to get up to speed on the XB-RR project, and it came earlier de worn. with 500 miles on the motor after his second outing in the AMA series at Northern California s lnfineon Racewa),. There. he was again inside the top l0 before heading for retirement due to an electrical problem - and not the son caused by a broken crank preventing the generator from spinning! Crevier's bike. however, was much fresher and l0 hP more powedul, showing 152 hp at the rear wheel at 8000 rpm on the Buell dynojet the day before the test. The XB-RR is a ver,, different kind of motorcycle than the water-cooled 60- degree V-twin Superbike lhat l'd previous- ly sampled at Buell's local Blackhawk Farms test circLrit. the bike that went on to donate its eight-valve motor to the V-Rod, for the XB-RR is a seeminS,y contradictory blend of ancient and modern. It's an air-cooled l3l9cc 45-degree pushrod V-twin shoehorned into a frame with the overall dimensions of a 250cc GP racer that features a host oftechnical inno- vation (see technical sidebar). The Buell XB-RR comprises so many radical solu- tions to motorcycle race design and pack- aging, without flirting Tesi-style with the avowedly unconventional or downright impractical, that it can truly be said to be CYCLE NEWS . AUGUST 2, 2006 65 L. Very 25ocr GP 25O-\ ' r-J] lAlan Cathcart _._.r That's equally the case when you rev the Buell hard, as you soon learn you must do all the time, in every gear, to ge! access to the undoubted reserves of performance ready to be extracted from that air-cooled motor. It s not that there's no power low down - the XB-RR will drive okay out of a slow turn from 4000 revs upward - but there's much greater punch delivered up high, with torque peaking at 6500 rpm. and holding up well beyond that mark- So ifyou want seriou! performance, you need to keep the Buell spinning above 5800 rPm all the time, which isn't necessarily an easy task with just a Iive-speed gearbox that has no choice of alternative ratios. And that's especially the case with peak power of 150-plus hp delivered at 8000 rpm. mean- ing there's an effective mean powerband of iusr 2200 revs. With a relatively slow- revving motor like this, that's not so much of a problem, but it does mean you have to be very precise and committed to the way in which you ride the XB-RR. Above all, you have to maintain cornering speeds at all costs. This would make front suspension setup a key factor in cutting fast laP times, especially at tighter tracks, and l''lcwilliams' experience in the white heat of 250cc GP racrng would surely come in useful aboard the Buell. The well-mapped Siemens EFI doesn't produce a ierky pickup from a closed throttle, as on some other fueliniected bikes. and the XB-RR niotor has a little bit o{ overrev The soft-action revjimiter arrives at 8200 rpm, with a harder one at 8400 rpm, which is useful for holdin8 a \ \ D ) I I tl this summer. with l"lcwilliams' bike a lit- l' t r

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