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/126264
, Mike Bell pushes the YZ 125 D to the limits at Saddleback. . :; ... -- " 0 ' , The YZ125D Yamaha is a direct result of the successful factory racing program of Bob Hannah and Yamaha. Not until recentlycould anyone hope of purchasing anything close to what the pros were riding, This did , however, g ive a lot of people a con veni ent excuse: "If I had a bik e like th at I co u ld go j ust as fa st" ," How many tim es ha ve you heard tha t lin e? We ll, it's put -up or shut -u p time at Yama ha , Except for t he water coo ling, t he' 77 YZO is rem a rka bly simi la r to t he one ca m paigned by Hann a h last yea r a nd even closer 10 th e on<; he rides in ~ he cu rrent 125 Na tiona ls, W at er coo lmg is a very sec re tive subject ' at Yam a ha . Wh ile ta lki ng to o ne of thei r mechan ics, his know ledge of t he bike was indeed impressi ve, ho wever, when q uestioned about the possibility of water in fut u re models, th is former learned person was struck with the fastest case of a nmesia ever recorded in the annals of medical history. The fact docs rem ain that some of the water cooled type parts that were on Hannah's bike last year are present on the 125s now offered by Ya maha . Whether t hese are a few carry-over parts or an actual move toward wa ter cooling in the futu re remai ns 10 be see n . The cost of implimenting such a major changein production would be high . T he YZO was easy to ri de a nd handled we ll o n th e tra ck , T he ha nd le b ars bo lt o nto th e steeri ng co lu m n behind th e forks , not on top , giving very' q uick turning . Inside lines on turns can now be yours . Our first impression s of th e bik e were great. T he ro ugh parts of th e trac k didn ' t seem bad u n t il we wa tched someone else ride th e sa me sec tion, and re a lized that th e suspensio n was workin g overt ime . When stock suspe nsio n comes th is good fro m th e factory it's easy to get reall y pi ck e y abou t com p lai n ts. Re ber the first bike you tried to m a ke into a mot ocrosser? Co mpare that with what is availab le today, I( s enough to make you cry , T he gap between the fac to ry racing progra m and th e actual production is gett ing. sm a ller e ac h year , The YZO 's pressurized air /oil leading-ax le forks are plush and ha ve t he exa ct "dyne -curve" as Marzocch i's, which shou ld tell you' some t hing a bo ut t he fro nt end. In int erm edi at e race action t he for ks rebou nded too fas t a nd top ped o ut a few times, l a t e r , t hree additional pounds of air press ure wer e added a nd the problem disappeared . O n the other end th e de Carbontype nitrogen / oil monoshock is also impressive - up to a point. That po int is in the rough with the power off. A small amount of swapping was encountered , nothing ha iry but not as st raight as an arrow either. At the rear of the YZO lies the main difference between the bike you can bu y and the one campaigned by Hannah in the Florid a W int er -AMA Series. O n the works bikes the mon oshock top sec tion is alum inum , reducing weight and a llowi ng better cooling. As we all kn ow , shoc k heat ca uses damp ing fa de , Also, not ed on Ha nnah's 125 at Hangt own were rem ot e oi l reservoirs. T he pro du ct ion un its ha ve steel tops', whi ch are heav ier a nd hotter; and offer no rem ot e oi l reservoirs. Another problem t ha t co uld cause fadi ng is th e presen ce of air in the oil secti on of t he monoshock. T he least a mount of a ir will m ix with t he oil under race co ndi tio ns a nd ca use the shock 10 fade in perhaps 30 minutes of hard rid ing t he first time. T he next time , with suc h a co nd ition, mayb e it would take only 20 m inutes un til th e mon osh o ck fades. Th is trend co ntinues unt il the shock is a conti nua l-