inertia of having the weight further out on the rim, and the heat generation near the tire, were not negative factors, based on testing. Askenazi concluded that testing and race track experience had proven the ZTL to be “state of the art.” Other industry innovations introduced by Buell in the XB lineup were the “fuel in frame” technology, and the dual use of the swingarm as an oil tank. Also, all Buell models feature a muffler mounted below the engine which helps keep mass centralized with some models featuring a computer-controlled valve to switch between two exhaust paths as necessary to maximize torque. Buell designs focus on providing good handling, comfortable riding, easy maintenance, and street-friendly real- world performance. Buell motorcycles were engineered with an emphasis on what they called the “Trilogy of Tech”: mass centralization, low unsprung weight, and frame rigidity. Buell engines were designed to be street-friendly both in fuel efficiency (up to 70 mpg-US or 3.4 L/100 km or 84 mpg-imp with the Blast), and in torque (the 1,203 cc version produces 110 N·m or 81 lbf·ft). They are also simple and easy to maintain. Most Buell two- cylinder engines utilize computer controlled ducted forced air cooling (variable speed fan that only activates as required), two valves per cylinder, a single throttle body, zero maintenance hydraulic valve actuation, and zero maintenance gear-driven cams. Buell Models RW 750 Road Warrior (1984) The RW 750 was a development of the Barton Formula One racing motorcycle.[18] Buell bought the parts and tooling from the failed Barton concern and developed the RW 750 for his own use and for sale to private entrants.[19] The engine was a liquid- cooled two-stroke square four. Buell’s development resulted in a more competitive racer, but production ceased when the AMA discontinued the Formula One class. RR 1000 Battletwin (1987–1988) The RR 1000 Battletwin was a street sportbike using a modified Road Warrior chassis and a Harley-Davidson XR1000 engine. Buell invented the Isoplanar engine mounting system to allow the heavy, vibration-prone engine to be used as a structural member of the frame without transmitting the engine vibrations to the frame. Lack of space caused Buell to put the suspension components under the engine. The linkage caused the spring and the shock absorber to extend when the wheel went up. Variations on the RR 1000 Battletwin include the RR 1200 Battletwin (1988– 1990), the RS 1200 Westwind (1989), the RS 1200/5 Westwind (1990–1992) and the RSS 1200 Westwind (1991). S2 Thunderbolt (1994–1995) Two-seater with Road Warrior based chassis and Sportster engine. The S2T Thunderbolt (1995–1996) was a touring version, with saddlebags. The S2 was very expensive to develop (around $100,000), and 1,399 units were sold in the first year—well over the 300 units Buell had projected. Buell S1 White Lightning The S1 Lightning was a more fundamental sportbike than the S3 Thunderbolt and M2 Cyclone that it was marketed alongside and the production on this model was stopped at 5000 after only 3 years. Variants of this version of the Lightning were the S1 Lightning (1996/1997/1998) and the S1W White Lightning (1998). The S1W came with a larger tank and Thunderstorm cylinder heads which gave an extra 10 hp (7.5 kW). X1 Lightning (1999–2002) The X1 Lightning was the successor to the S1 Lightning line. They all used the Thunderstorm heads, fuel injection (Dynamic Digital Fuel Injection) and incorporated larger fuel tanks as well as completely different body designs. The most recognizable frame piece was the brushed aluminum tail section that swept upward and back underneath the two-up seat. The 1999 X1 Lightning was awarded motorcycle of the year in Japan. S3 Thunderbolt (1997–2002) S3T Thunderbolt (1997–2000) 1999 Buell S3 Thunderbolt Buehl