Cycle News - Archive Issues - 1990's

TECHNICAL Commonwealth Honda Con tinued from page 25. wi th th e larger bore, a set of speciallyground Megacycle cams (with 105degree lob e centers vs. th e sto cker's 98 degrees) were installed, upping output to nearly 100 hp (measured a t th e rea r wh eel o n H onda Racing's dyno.) It sho uld be noted th at a t both Da yton a (a fas t, lo n g tr ack ) a n d Loudon (a short , twi st y track ), th e a ircoo led, SOHC, valve-spring, ca rbureted ma chine proved to be as quick as it s water -co ol ed , fu e l- inj ect ed , DOH C , desmodrorni c o p pos itio n , mu ch to th e d eli ght of th e non Italophi les. Al th ou gh a n 897cc mo tor with I mm la rger valv es was built, it crac ked a liner in its firs t practi ce a t Heartland Park Topeka , Kansas. It was determ in ed that this would probably be a recurrin g problem due to th e fact that th e I in ers had to be made so th in , so the bore stayed at 86mm. I An increase in stro ke was o u t o f the q uestio n sin ce piston spee ds 'a t its 10,000 rp m red line were a lrea dy in th e' , '48-4900 ft.lmin. range, so sh ort of cas ting new cylinders it appears that the machine has reach ed its practi cal disp lacem ent lim it. Co n vert ing th e gea rbo x b ack to five speeds was simpl y a matter o f retro fitting th e origina l gea rs from th e Pari s-Dakar mot or. In its first in car na tion , th e gearbox had round dogs a nd too low a first gea r; th e seco nd ~ers ion Iea tu red .a taller first gea r a nd cl o se r spaci ng between th ird a nd fo urt h. Wh at Adams calle d th e " MK in" version o f th e gea rbo x now graces the bike: it has square dogs a nd closer fourth a nd fifth gea rs, and works very wel l. H onda offered a hi gh er-ratio » im arv for th e dirt tra ckers, a nd th is Is used on th e machine. Although the team broke th ree cran ks in 1989 (all in practice), it would be unfair to cal l the engi nes fragi le. Plumb obtained a slew of used cranks from dirt trackers - new cran ks are $3000, so used ones were a good deal. Each crank has over $1000 worth of slugs of u ltra-heavy Mallory metal (a trade name for sintered tunsten ) pressed into milled holes to add mass and balanc e the crank. For road racing, heavy flywheels and cranks are a hinderance, so th e team milled weight off the extern al flywheel and the cente r crank cheek. • T her e Cast o f cha racters n wi th is little in co m mo building and renting Kentucky apartment ho uses and racing motorcycles. However , o ne ca n provide the fu nds to do th e ot her. To make mat ter s better, Adams' partners (h is two brothers) ta ke t a re of en o ug h of the day -to-day business to allow him to do what he loves - p lay with motorcycles. Adams figures he is about at his limit racing in the States, a nd as m uch as he' d lik e 1 see the world, it's not likely he ' ll 0 have the time to do any international level racing. As it is, the seven-race '89 T wins series cost him $50,000 (not incl ud ing the cost of th e mach in e) a nd Huge amounts o f time and energy, so It is daunting to co nside r wh at a n int ern a tio na l effort would require. As mu ch as Adams admired Lewis, it was p robab ly better for the tea m tha t Renfrow rode the bike after Dayton a. Lewis had returned to Englan d for a promised ride (which fell thr ou gh ) in the World Superbike Series" leavin g Adams without a rider. With a p roven conte nder, thanks to Lewis' strong, seco nd -p lace showi ng a t Da ytona , Adams was able to a ttract seriou s talent. Althou gh Renfrow won hi s two previou s U.S. titl es on GP bikes (1983 E-2 champ o n a Yamaha T Z250; '86 f.-I. cham p a boa rd a Honda RS500), he also spent two year s racing a Su zuki su perbike for Van ce & Hines. Furthermo re, Renfrow a nd (ironica lly) hi s ch ief rival Q uarterley teamed up on a Honda RC30 to become the highestp lacing Americans at the '89 Suzuka Eight-Hour; Renfro w a lso led th e WE RA 24 -Hour We st at Willow Springs before o ne o f his teammat es cra she d, destroying th e machine. The exper ience Re nfrow has ga ined through the wid e var iet y of eq uip ment he's ridden ha s made him a valuable development rid er. Adams figures tha t th e sort ing out Renfrow a nd Plum b did this year was in strumental in th eir succ ess. P lumb is one of th e unsung heroes of racing. Although hi s official title at T eam H onda is " Tech nica l A: ' he is a bit of everything to everyone. He built Shobert's engines, ran the dyno, hel ped th e dirt trac k boy s, a nd even did development work o n th e rnotocrossers. For the most part, Plumb 's work o n th e Commonwealth Honda was done o n his own time until la te in the seaso n ' when H onda began send ing him to th e ra ces. On with th e show A change in AMA Pro Twins ru les for next year puts both classes on the track at the same time at most of the races ' (a ltho ugh promot ers hav e th e op tion to run the cla sses sep arately). Adams figures th at no sane professional wou ld go out on a track running into backma rkers going 40-p lus mph slower, so he is p ulling ou t. Dayton a Internationa l Speedway has announced that it will run separate races for the two classes, so the boys figure they'll run th e ' " Flying Banana" on e last tim e before putting it into semi-retirement. " Wha t's th e challenge in climbing the same mountain twice?" asks Adams, th ough he concedes tha t he might allow the bike to be taken to Europe for an outing a t Spa or Monza, provided sponsorship could be arranged. So o n to bigger a nd better th ings. After hinting that. they wo uld not sponsor an AMA Superbike Racing T eam in 1990 , Hon da agreed to support Ren fro w o n a Commonwealth Honda RC30. Although not a true works team, Commonwealth Racing will receive two R C30s (o ne of which wi ll likely be d ism embered for spares) and a sizeable quan tity . of spares. Adams must pay all other expenses, including Pl umb 's sa lary after Daytona (H onda has agreed to pay Plumb to prepare the bikes for Dayto na ). In the past, Plumb has done almost all the work on his own tim e whi le working hi s regu la r job a t American Honda . It is up to Ada ms to secure sponsorship for the year, a nd alt hough he' has no maj or sponsors a t th is time, he is working on that p roject wi th hi s ' usua l di ligence and professionalism. , Curtain call T he Commonwea'l th H o nda is now fast, reliable, li gh t, pre tt y and a relatively good hand ler . Of all th e oneoffs a nd wanna-be project bikes that ca me to Da ytona in '89 , this o ne delivered th e goods, proving that a se mi -p r i va tee r " b its a" can work, pro vided one is will ing to devote th e necessar y time a nd mon ey - a nd ,to hire the right peopl e. Twins raci ng at least in the G P cla ss - has grown . beyond the o ne person-team level. Many have criticized Adam s and Honda for " buyi ng" a nothe r raci ng ti tie, but those peop le are q uick to fo rget how mu ch time a nd money have go ne into Dr . J o h n 's Mo toGuui or th e 851 Du catis, Real is tica ll y, the Co m mon wea lt h bike was chea pe r to p ro du ce than the Italia n bikes. Adams pi cked a good engi ne, co u p led it wi th a n excellen t me chanic and an experi ence d rider, a nd organized th e cong lo mera tio n into a winning effort . 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