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/126810
TErt YEARS AGO Suzuki's Barr y Sheene was severel y injured a t a Da ytona test sessio n , su ffering a bro ken left leg . co lla r ho ne, rib a nd wris t. Sh een e spilled near the start-finish line at 170 mph whe n hi s rear tire shredded. All teams were busy prepa ring for th e Daytona 200 classic. with th e co nt est for the checke re d ex pecte d to be . betw e en Yam aha rid er s Kenn y Robert s and Giacomo Agostini. Both Robert s and Ago are ex peered to use bi kes featu ring a m onosh ock rea r suspension - th e rest of Yamah a 's team bikes will have co nve nt io na l suspen sions. Pau l Smart a nd C liff Carr have been dropped from Suzuki 's team; Gary Nixon a nd David Aldana will be wea rin g th e blue a n d white Suzu ki co lors . Yvon Du H arn el and Jim Evans w ill be riding team Kaw asaki KR750s, a nd Kurt Liebman a nd Reg Pridmore will be aboard ult ra -tri ck BMW 750cc G P bi kes. As o f th is time. H onda . NOrian-Trium p h a nd Harlev-Davidson ha ve not entered factor y efforts in thi s year's 200. ANNOUNCING ASLICK SOWTION TO THE PRODUCTION RACING PROBLEM. The racing probl em, of co urse, is to get a street legal tire with enough stick to give you the traction and rood holding you need for maximu m speed an d safety. Rain or shine. Toso lve the probl em, we turned to the best expe rt we co uld find : our own rac ing slick, A s you can see in the pho to, the stresses (or for ces) that acted on our slick d uring a race left ripples on its surface . These ripples run perp end iculor to the di rectio n of the forces . And they fall into 3 gro ups: 1. The for ces from acce leration on the straig htawa y. 2. The fo rces from occelerot ion plus co rnering on C UNes. 3. The fo rces of co rnering at full lean . By precisely shaping tread grooves to follow those force lines, we created a new tire tha t is exceptionally stab le and squirm-free under ra cing stress conditions. Becau se it squir ms less, there's less heat buildup from interna l friction. And that. in turn, allows us to use the same soft sticky rubber co mpo und tha t w e have on our slick. The fron t tire has many deep grooves a t the center for straig ht line w at er di spersal at speed . Both tread dep th and amount o f grooving are progressively ' reduced toward the sho ulde r for co rnering stab ility. . On both tires, groov ing disa ppe ars at the sho ulde r. more rub ber is on the ground, an d the tires oct like slicks. WE TRANSLATED THE STRESSES ON OUR SLICK INTO AWHOLE NEW KIND OF REAR TIRE. INTRODUCING THE MICHELIN HI-SPORT. ABSENa OF GROOVING AT SHOUlDER lAREA3 ABOVE) . AllOWS MAXIMUM TREAD ' CONTACT AND STABILITY AT EXTREME LEAN ANGLES. CENTER ANDU-GROOVES FOLLOW UNES OF FORa ACTING ON nil (AR£AS 1 AND 2 ABOVE) FOR MINIMUM TREAD MOVEMENT AND MAXIMUM WATER DlSPfRSAL GRADUAL REDUCTION Moto Villa entered th e lJ .S. ma rket . intro du cing 250cc a nd 480cc moto cross machin es. Both bik es were tested , a nd the big Mot a Vill a wa s found to produ ce 53 horsepo wer. R evi ew er John Huerter co m me nted : " T his is more power than a ny rid eabl e m o tocross engine we kn ow a bo u t or ever care to hear a bo ut. " A crowd of 48.000 packed into T exas Stadium in Irving , T ex as for th e 1975 Yamaha Super Ser ies o f Mot ocross. Ca n-Am m ounted J imm y Ellis co mpletely domi na ted the four-mote 250cc cla ss, with three wins a nd a second 'p lace fin ish behind Ma rty Smit h. Ste ve Stackable too k hi s n ew factory Mai co G P400 to the Open cla ss victory, winning a fter a last -lap cla sh with T on y DiStefa n o iri the firs t moto , It appeared th at Stack ab le blocked DtS tefano, ca usin g h im to crash. but actually DiSte fano's gea rbox pa cked up a nd ca u sed th e fall. The CMC h osted a priva teer da y at Will ow Spri ngs , and inaugura ted a four-strok e G P class " . . . designed to get a ll th ose o ld Manx Nortons out of peoples' garages." T he new class was wo n by .Kaming Ko a board a 500cc Yoshimura Honda, fo llowed by Da vid Breetwor a nd his John Pl a yer Norton . Dick Pe arce won the 125/ 200 G P race ri d ing a Greeves Silverstone - a bike that. was as o ld as many o f the ride rs in that cla ss. Bob Ba len tin e wo n the overa ll at the DRA Triple Hare Scrambles held a t California City. Kevin Hasten was clea rly th e fas test o f a large group of Experts enteri ng the event. bu t on the third loo p h is brake cabl e snagged . locked the fro nt brake full on. and sent hi m into a bru tal high -speed crash . T hough sha ken up. H asten recovered an d p laced seco nd overa ll a ni! first O pe n Expert. Ben ny Padilla nursed a sic k transmission around the la st loop to 'ta ke third place. .' INAMOUNT AND DEPTH OF GROOVING GMS CORNERING STABILITY. TG22 (REARl TFU(fRONT) MICHELIN. BECAUSE SO MUCH IS RIDING ON YOUR TIRES. ------------------------------------------- • ARTS ' ACCESSORIES SAlES' S ERVICE P .. .. BELlfLOWER YAMAHA • TOURING' Serving A ll of Southern Californi. STREET ' OFf..ROAD PRIC~u!'l~!!r~y~!yHERE ~ --... $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ Comple te Insur ance & Financing A vailabl e All Pric•• + tax. Iicen... d oc tH . 1TIaI..-.. •1t.JS . n U 5 .... -........ SHDE ElU I tw.m19!U5 $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ IEUfLOWERYAMAHA 10401 E.AIondra • IleIIlIoww,CA(213) 925-6097 .• SAVE 1crr. All Pa rts o!l Accessories . .. W1thThIS ~,0fIer~~~S4.J1.as Visit Our New . , 0.' ~~$ . $$ ~IV Slln (213) '6~ 6'~7 . : .~ • I-i . I , 19