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/126062
E ~ ~ 125GP pocket rocket; § Yamaha TA-125 barely ~ ~ ~ bO ;j -< 34 W By John Ulr ich hen Philippe deLespin ay first showed up with his wat er-cooled 125cc Yamaha GP racer at a Southern Californi a club race, his competition snickered. DeLespinay was not th e first to bring such a machine to Ontario Motor Sp eedwa y. But the competition, which at th e time th ou ght its finely-honed air-cooled TA 125s invincible, had not counted on deLespinay 's skill as a one-man R&D department. It took deLespinay three races of sorting-out before his bike could beat the air-cooleds run by Dan Spisak, John Lassak, and Doug Draper in AFM road racing. But suddenly, deLespinay was winning, and winning big. Al though he says the bike is still in early stages of development. deLespinay's machine is simply the fastest, best-handling machine on th e tarmac in Southern Cali fornia, and probably in the Uni te d States. Once you take a close look, it 's easy to see wh y. Wet, with water in the KR250 Kawasaki radiator, the bike weighs 180 pounds (d ry , it weighs 165 ). DeLespinay is helped in racing this remarkable machine by several sponsors. Cal ifornia Cycle Center of Santa Ana, California picks up the tab for parts. Hurley Wilvert helped re-design the fram e geometry, built the high-rpm pipes, and modified the carbs, fork, and shocks. The brazed Reynolds 5130 frame started as a Jack Machin racing frame from England. DeLespinay and Wilvert worked with C&J Frames to change the head angle , reinforce the frame for added rigidity, and alter the swingarm to ac cept 40 degree lay-down rear shocks for 5" of travel (opp osed to l y," stock). The frame is very narrow at the rear-sets, adding to ground clearance. Wilvert and deLespinay modified the fork for what deLespinay describes as constant damping, as opposed to progressive damping. In other words, damping is constant no matter what the st age of fork compression. The system, which deLespinay calls "revolutionary," employs dual valving. Wilvert set up the shocks the sam e way, (d ual valve ) out of Mulholland parts. The 30mm Mikuni carbs were shortened I " at the front of the carb bore, for the effect o f short air in tak e for the cylinder. The front brakes are twin 2025T6 aluminum discs unp lat ed - from France, with Ho nda C B50 0 calipers an d pucks. The bra ke set- up has been used in its current form (with the sam e discs, calip ers, and pads) on various 125GP bikes rid den by deLespinay during the last t wo years. ' "I can o u t brake everybody in the field qu ite eas ily with this brake," says deLespin ay. He can also go around comers faster, ' than ks to th e frame and th e 2. 75 X 18 Fre nc h Du nlop K81 soft-compoun d tires supplied by Harry Hu nt. The fairing is a highl y -modi fied Marty Lunde model. The shield is unbreakable polys tyrene. The real trickery comes in the engine. The water-coo led cy linder an d head came fro m Fra nce. DeL espinay built th e wa ter pump hims elf. The r ad iat or is off a KR250 Kawasa ki. A stock Yamaha TA 125 cran k was rebuilt us ing different bearings, ones deLespi nay feels 'are higher quality. The cases were milled and matched unt il no transmission shims were necessary, with o n ly a few cra n k shims required. T wo of th e five gears - firs t and fifth - are Martin Engineerin g replacements from Eng lan d, with a wider-than-stock spread . The other three ar e stock Yamaha parts machined to a p eak fo r minimum runningresistance and maximum ease of shifting. Stock Yamaha pistons are shot peened for strength to wit hstan d the 16,000 red line used with the Wilver t rpm p ipes. The p istons are Xvrayed whenever th e engine is ap art. DeLespinay says that he runs the bike very rich "to keep it together lo nger. " He estimates that an additi o nal 10-15 mph are available if the bike is jetted properly, but he points o ut that the one tim e he did dial in th e jetting pe rfectly, the crank broke (in o ne o f 'th e first three races he ran with th e bike ). Geared 16-37 like several TA I 25s in the clas s, deLespinay 's bike is noticably faster in top en d. His be st lap time on the long version of On tario's ro ad cou rse was 2:25. According to our clocks , if de Lesp in ay had run his 125 in 250 GP that day, he would have co me in eighth in 250 GP with 2:2 5 lap tim es. His lap t im es were co mp arable to those turned by t he 750cc T riump h Trident that won the AFM Six-Hour ro ad race in Ap ril of this. ear, , .. (Above ) The Garbage Can Spe cial o r GCS is the handiwork of t he Count Philippe de Lespinay . (Left) H1R clutch and hand made wate r pump. Honda's 941RCB $2 million marathon runners F rench co rresponden t Ph illipe De Harle rep ort s th at Hon da ex p ec t to spend abou t ·1 2 million four-bik e Coupe on i ts d'Endurance team of racers in 19 76. At this writing, that expenditure had netted them victories at the 1,000 km of M ugello by the team of Lean f Chemarin and at th e Woods Barcelona 24·hour by S tan '(shown}/Charlie lVilliams. DO /fC fo urs, designated T he "RCB 750 ", actually displace 94 1cc and weigh 360 po un ds read y to race. Th e tires Barcel ona w ere th ey were run ning at han d-gro oved Dunlop KR slicks. ' Th e engine breath es through fou r C V Keih ins and e x hau sts into a m on st er co llecto r/muffler. No word on th e d b rat ing.