From a press release issued by Dr. Rob Tuluie:
Setup, Setback and Win – Robert Jensen Wins on the Tul-aris!
The first CRA race weekend of 2003 at the Mid-America Motorplex saw Robert Jensen setting the pace all weekend long. Upon arrival at the flowing circuit, we were greeted with perfect sunny racing weather and further improved facilities. First, Robert practiced on the Tul-aris and his own stable of bikes, a Yamaha R1, R6 and Suzuki GSXR750. Throughout Thursday and Friday practice Robert was consistently faster on the Tul-aris than his own bikes by ½ to 1 second. This is remarkable since Robert has much more seat time racing 4-strokes and yet he was turning the fastest times on the less familiar Tul-aris. As times were coming down for all bikes and riders, Robert was still lapping faster on the Tul-aris than anyone else, including such top national privateers as R1-mounted Larry Denning and Shawn Conrad.
We were making gains with rear suspension linkage ratio adjustments, suspension damping adjustments, brake feel and jetting. In particular, we found that a new Tul-aris linkage ratio, machined by Tul-aris team member Tim Wirtz, offered better stability and drives out of the turns. We make fine adjustments to the linkage ratio by using a quick-change eccentric adjustment in the linkage. Once we found a good ratio, we worked on our Ohlins suspension’s damping adjustments until brake stability and cornering traction were on par. We also improved brake feel by changing brake pad compound and adjusting the GP Tech/AP Racing adjustable radial master cylinder’s lever ratio, a very convenient feature which has proven quite helpful in tuning for just the right amount of brake bite and power.
On the other hand, our Michelin tires worked excellent all day and our first set was good for over 100 racing miles, when other tire brands were being torn up rapidly by the abrasive track surface. Likewise, the Hot Seat Performance Polaris 800cc motor, powered with Nutec GP2 fuel, worked excellent, with awesome acceleration and long, multi-gear power wheelies – which is where the trouble started:
Coming out of the 2nd gear turn onto the front straight, an exuberant Robert wheelied, short shifted into 3rd, continued to wheelie into 4th at which point the front wheel started heading towards earth again – all of it well document by the on-board data acquisition system (see enclosed graph). The problem was that the front wheel was going 80 mph when first lofted into the air and then didn’t touch the ground until Robert was up to 115 mph. Unfortunately, the steering was turned slightly to the side, so when the 80 (or less) mph front wheel hit the 115 mph pavement it instantly skidded, and Robert fell down. He was fine, but the bike was caked in mud. Thankfully the Tul-aris was not damaged too badly, but Tul-aris team member Dave Heisserer and I spend many, many hours disassembling and removing mud and sand from everything, including the crankcase. Hence we spend all of Saturday working on getting the bike back together and missed valuable setup time.
Two quick runs down the handy Mid-America drag strip Saturday night at 11pm by yours truly, in front of an assembled crowd of local burnout enthusiasts, confirmed that the motor was functional. The sight, sound and smell of the Tul-aris seemed like a UFO in this alien environment, with the real purpose of this endeavor known to few. Let’s just say that the Tul-aris launches about as well as a lowly ’79 Pinto.
With one short Sunday morning practice relegated to a quick functional check of the bike, we were no longer the fastest bike on the track and a small miracle would have to happen in order for Robert to pull out a win. We decided to use our first race for practice and focus on the 2nd race, the feature Unlimited GP race. The problem was that we only had 20 minutes between races to make adjustments. As soon as Robert came in from the practice-race, we adjusted the shock linkage ratio (3 min), suspension damping (1 min), brake pad compound (2 min), shock spring preload (1 min), refueled (1 min), ignition timing (3 min), and tire warmers and lowers on/off (1 min each) – not bad for a volunteer crew! Of course Roberts’s perceptive and detailed feedback helped in setting us onto the right track and setup decisions were made quickly thereafter.
The start of the Unlimited GP race found Robert in 3rd place, but he quickly moved past the leaders and was leading the race after the first lap. He was lapping 2 seconds faster than he did just minutes earlier in the practice-race, so our quick adjustments paid off. Almost immediately, Robert pulled out a big lead. Robert was able to make up time in quick left/right transitions and with his unmatched ability to get super drives out of the turns. It was exciting to see him transition from full left lean to full right lean much faster than anyone else, then roll on the throttle at a lean angle that seemed to defy what normal ability, tires and suspension offer. Robert won the 8-lap race with a 7 second advantage over 2nd place, CRA #1 plate holder Scott Ruehle on a Yamaha R1. In addition, Robert won every race he entered on his own bikes, save for the practice-race on the Tul-aris and an unfortunate DQ on one of his own bikes in another race.
The big winners this weekend were Robert Jensen, Michelin, and all others who helped this effort: MotoDynamics, Nutec Racing Fuel, Ohlins USA, Hot Seat Performance, Lofgren Racing/Manley Cycle, GP Tech, Yoyodyne Titanium, Mason Racing Tires, MTS Systems Corporation, Carbon Fiber Specialties Products, DCM Services and Deus Ex Machina. Special thanks to Eric Christensen, Brian Gillingham and Chad Pierce at Polaris as well as a special thanks to Dave Heisserer for this exhausting, but ultimately successful racing weekend.
Robert Jensen is sponsored by Butler Machinery, Michelin, Arai Helmets, RS-Taichi Leathers and Sidi Boots.
Our next race is the largest CCS road racing event of the year, on April 25-27 at Road America, north of Milwaukee, WI.
