Cycle News is a weekly magazine that covers all aspects of motorcycling including Supercross, Motocross and MotoGP as well as new motorcycles
Issue link: https://magazine.cyclenews.com/i/128331
AHA Pro Racing issued a competition bulletin that's first sente nce says much of what you need to know about the AMA rulebook. "Due to possib le confusion created by informat ion released by AMA Pro Racing prior to the publ ication of th e 2004 Road Race Rulebook, th is bulletin is being published as a clarification of the permitted modificat ions to swingarms in the Formula Xtreme class." The issue came to a head at Road America where the Hondas of Miguel Duhamel, Jake Zemke and Alex Gobert and the Valvoline Suzuki of Vincent Haskovec were scruti- nized . The Hondas had clearly been altered, but w ithin the rules, t he teams believed. The AHA seemed to agree, choosing not to penalize the teams while letting them know that they cou ld no longer use the swingarms. The decision was interpreted by rival teams as a capitulation to Honda. Honda's out was the "po ssible confusion" in reading the rulebook. The rule was changed to facilitate the use of the larger Superbike tires that some bikes, specifically the Honda CBR600RR, use . In the end the rule stated that "Stoc k swingarms must be utilized . The only modifications perm itted are gusseting. attachment of stand mounts, and to allow the fitme nt of nonstock brake components, spacers, axles and wheels. Any such modifications may not alter the fore and aft axle adjustment d imensions or any other pivot or linkage location s from that of the stock swingarm. 1000cc1350 cc air-cooled twi n-cylinder motorcycles are unrestricted." The wording allows as libe ral modification s as before, according Ducati Austin's Eric Bo strom jetted to France from the Canadian Formula One Grand Prix, ho ping to sort out his seasonlong hand ling problems. "We tried several things , mainly in the front to suit his riding style o r the motorcycle," said Jean Herisse, Michelin's po int man for AMA racing . "That was the goal. " Herisse said between the front and rear, Bostrom tried 30 tires. "We tr ied nearly everything. Up to now, he's been using the same tires as GP.The weekend we 're trying different stuff to suit him on the Ducati.' Bostrom rode a facto ry Duca ti that do esn't be long to the race team. They also had the use of the Fila Ducati F04 of Regis Laconi, which they scavenged for suspension parts. "So few times can you jump on another rider 's suspension and fee l good straight away," Bostrom said. "O n my out lap, I'm like, 'Wow th is thing's pretty close to my bike. " The test track is mostly second and third gear, with long, flow ing corners all hidden by a sea of tall grass . "T he track was difficult to learn , eve n though it was a short lap time ," Bostrom said o f the just over one- minute lap times. The first day was spent getting the bike set up , the second on testing. Michelin th rew tires at Bost ro m , one after another, asking him to ma ke snap decisions . "It's amazing how good you get at go ing out and getting up to speed straight away even on a front tire that you've never seen before," he said. "If you ask any rider, testing front tires is the mo st difficult part of our job. But you get the feel stra ight away." Bostrom said he never got on a front tire incorporating any air management qualities that was intimidating. "In t he end we found a tire that is new family of tire for Michelin that I believe Colin [Edwards] had in the first rider tests just a w eek or so before I had been there," Bostrom said, "and he seemed happy w ith the tire , and I'm very happy w ith the tire. I know we have a great front tire . And the rear tire's be en good all along . Now it's just a matter of getting me and the bike there." Michelin brought two of the fronts from the test, and Bostrom likes one in particular. "It's pretty close to the tire I was running on, but just seems to complement the bike a little bit better. It seems like it just turns in a little bit easier and apexes a little bit easier." The only downside was tha t they'd just cut the grass, and it caused Bostrom's hay fever to flare up . ':A.fter riding o ne of those laps, my eyes they were as red as the bike ." The re 's a chance he 'll be hea ding back to Europe in July for another new such as downforce-producing deflectors o r generation of tires to test. to Erion Honda's Kevin Erion. "The new, rev ised version of the rules clearly allow s me to do exactly what I did to the first swingarms, t. Erion said. Not know ing w hat the new rule would be , and w ith the AMA in possession of one of the pieces, Erion had to build four sw ingarms for Brainerd. "Once they actually put in the clarification to the rule , t he sw ingarms we had from day one at Daytona, as far as I'm concerned, are perfect ." The swingarms that Erion's te am built in less than a week used all the parts they had on the previous swingarms. There was further clarification of an existing rule regarding fork b race s in Supersport and Superstock. The clarification states that "Fork braces must funct ion so lely as a strengthening device for the fro nt fork structure . Braces duetsthat redirect incomingair are not permitted . The determination of air management qualities will be at the sole discretion of the race manager and the chief technical inspec tor." The rule was aimed squarely at the Yoshimura Suzuki GSX-RI000 of Ben Spies, though no one in the Yosh cam p could find any support for the notion that the brace provided any downforce advantage. The part was first scrutinized at Fontana back in early April. Only the week be fore BIRwas the team told that they cou ldn't use it due to the aerodynamic advantage. From the start, Yosh disagreed , and at so me point , the AHA came aro und. After very light modifications, the AMA issued yet another statement, th is one saying the for k brakes were acce pta ble and legal. All it took was some fiberglass and foam rub ber. T he team fashioned a more bulky, squared-o ff to p o f the bra ce, taking away what was perceived as the aerodynamically angled advantage. Erion Honda's Ja ke Zem ke didn't know what was wrong w ith his tires when the race ended at Road Ame rica, but he knew something was drasticallywrong. So wrong that he co nsidered pulling in. T ires being the probl em, Ho nda met w ith Du nlop immediately afterward for an explanat ion. But it wasn't specifically a tire problem. "Wh at happe ned was after t he restart when we changed our tires, the front tire, by t he end of the race ende d up spinning aroun d on the rim 180 degrees," Ze mke said, adding t hat it was vibra ting so badly that he co uldn' t tell if it was the front or the rear. "W e've seen rears do it befo re , but never the fron t. I didn't know w hat the pro blem was . Ali i knew is the bike started vibrating o n the second lap , and it kep t getting progressively w orse and w orse to t he po int t hat I could n't even see go ing down the straightaways. Th at' s not the tra ck you wan t t hat to hap pe n at . Road Continued on page 29 CYCLE N EW S • JULY 7, 2004 25