Yamaha YD-1

Pioneer twin

Old Bike Australasia - - FRONT PAGE - Story and pho­tos by Jim Scaysbrook

Notwith­stand­ing its rel­a­tive lack of ex­pe­ri­ence in the two-wheeled field, Yamaha had hit the ground run­ning with its ini­tial model, the DKW RT 125-in­spired YA1 125cc two stroke sin­gle. The pro­to­type YA1 had been mer­ci­lessly tested around the clock for 10,000 kilo­me­tres be­fore it went into pro­duc­tion to be sold un­der the cu­ri­ous ti­tle of Red Dragon­fly. Teams of sales rep­re­sen­ta­tives were sent through­out the length and breadth of Ja­pan, rid­ing Red Dragon­fly mod­els, to sign up deal­ers. It was no sim­ple task for a brand pri­mar­ily as­so­ci­ated with pianos, as the bikes were ex­pen­sive com­pared to the com­pe­ti­tion, and Yamaha’s terms of sale were strictly cash on de­liv­ery. By July 1955 the Yamaha Mo­tor Com­pany had been es­tab­lished as a sep­a­rate or­gan­i­sa­tion to the main mu­si­cal in­stru­ment com­pany, with 100 em­ploy­ees that turned out 300 mo­tor­cy­cles per month. By this time ex­ten­sive de­vel­op­ment had seen the power out­put of the YA1 rise from 5.5hp to 9hp, and soon a 175cc ver­sion, the YC1 was added. Some­what brashly, the com­pany en­tered both mod­els in the Mount Asama Hill Climb, a blast up a vol­cano north of Tokyo, and won not only the 125cc class, but the 250 class as well. Sales of both mod­els soared, but it soon be­came clear the YC1 had a man­u­fac­tur­ing fault in the si­lencer which sti­fled the en­gine. To rec­tify the prob­lem, the com­pany dis­patched me­chan­ics armed with a ‚

ham­mer and punch to call upon ev­ery sin­gle owner of a YC1, where­upon breather holes were pounded into the baf­fles to cure the prob­lem! That’s cus­tomer ser­vice for you. The ex­pan­sion into the 250cc mar­ket was there­fore a log­i­cal step, and Yamaha man­age­ment had their eyes on the Ger­man Adler MB 250; the highly suc­cess­ful par­al­lel twin two stroke dat­ing from 1954. How­ever while the ini­tial in­spi­ra­tion may have come from the Ger­man de­sign, the Yamaha en­gi­neers, af­ter suc­cess­fully pe­ti­tion­ing com­pany pres­i­dent Genichi Kawakami to be given a free hand in the fi­nal spec­i­fi­ca­tion. This was duly granted and full sized draw­ings were cre­ated to al­low en­gi­neers to con­struct pro­to­types in time for the sec­ond run­ning of the Mount Asama Road Race of 1957. Of­fi­cially, the only Adler fea­ture re­tained was the over­all de­sign of the crank­case, and the Asama bikes used full cradle tubu­lar steel frames with swing­ing arm rear sus­pen­sion and tele­scopic forks, whereas the Adler em­ployed plunger rear and lead­ing link front sus­pen­sion. For the Asama event, which had new rules for 1957, Yamaha en­tered two teams. The A team used a YA 125 and a YD-A 250 with a bore and stroke of 54mm x 54mm, while the B Team used a 125 and a YD-B with a re­vised bore and stroke of 56mm x 50mm. Like the Adler, the 250’s cylin­ders were steeply in­cluded, with gen­er­ous square finning, both en­gines run­ning a com­pres­sion ra­tio of 9.5:1. A sin­gle Mikuni car­bu­ret­tor with a re­mote bowl was used. Ig­ni­tion was by mag­neto on the right side of the crank, with the clutch mounted on the trans­mis­sion coun­ter­shaft, un­like the pro­duc­tion YD-1 model which had the clutch on the left side crank­shaft, Adler-style. To cope with the ash sur­face, 2.75 sec­tion stud­ded off-road tyres were fit­ted to the 18 inch wheels. To the de­light of the fledg­ling com­pany’s man­age­ment, Yamaha dom­i­nated the Asama event, fin­ish­ing 1-2 in the 125 class and 1-2-3 in the 250 class. In a speech to the Yamaha work­force, Pres­i­dent Kawakami said, “Since we lacked ex­pe­ri­ence in this type of busi­ness (mo­tor­cy­cles), we had to study the types of prod­ucts we would have to make. In our ef­forts to min­imise set­backs and shorten the time from en­try to prof­itabil­ity, we ob­served fac­to­ries in Ger­many. Af­ter ex­am­in­ing var­i­ous types of mo­tor­cy­cles, we made our first 125cc model, the YA-1. We were able to start out con­fi­dent that, af­ter thor­ough in­ves­ti­ga­tion and re­search, we would never be over­taken by our com­peti­tors.” He went on to say that the com­pany aimed to be the lead­ing mo­tor­cy­cle man­u­fac­turer in Ja­pan by 1959. From an ini­tial out­put of 200 bikes per month at their Ha­makita fac­tory which em­ployed just 274 peo­ple, the num­ber had swelled to more than 1 mil­lion an­nu­ally by 1975, with more than three quar­ters of that fig­ure ex­ported, and with a work­force of more than 8,000.

Nat­u­rally the US was seen as a key ex­port mar­ket, and as early as 1958 Yamaha sent five of their YD-A 250 twins to con­test the grandly ti­tled Catalina Grand Prix, a race over a rut­ted gravel track on the re­sort is­land off the coast of Cal­i­for­nia. Lead rider Itoh de­lighted the com­pany by fin­ish­ing sixth. The pro­duc­tion YD-1 that had been re­leased in 1957 in a rather un­usual dé­cor of brown and grey used a pressed steel back­bone frame with a tubu­lar steel swing­ing arm con­trolled by non-ad­justable shock ab­sorbers. At the front was a con­ven­tional tele­scopic fork. The en­gine was sus­pended from the chas­sis and re­tained by mounts at the rear of the crank­case and by a bracket connecting the rear of the cylin­der bar­rels. The twin ex­hausts fin­ished in long ta­pered mega­phones. Like the Adler, the YD-1 sported gen­er­ous mud­guards and a fully en­closed rear chain, as well as a sump­tu­ous dual seat. In a fur­ther step to­wards over­all clean­li­ness, the car­bu­ret­tor was com­pletely en­closed in a cast al­loy shroud, like sev­eral of the Euro­pean mod­els such as Maico, Adler and DKW. With a petrol/oil mix in th­ese days be­fore forced lu­bri­ca­tion be­came a two-stroke fea­ture, this kept the en­gine cases and the rear of the ma­chine free of oily muck. An­other ap­par­ent nod to Euro­pean prac­tise was the use of 16-inch wheels front and rear. In­stru­men­ta­tion con­sisted of a Yamaha-badged Auto Me­ter speedome­ter with trip me­ter. 12 volt electrics and a stan­dard push-but­ton elec­tric starter were prac­ti­cal in­clu­sions that made good mar­ket­ing sense, and turn signals front and rear were also stan­dard equip­ment. The pressed steel chas­sis YD-1 lasted only a year or so be­fore a com­pletely re­vised YD-2 ver­sion ap­peared in De­cem­ber 1958 with a tubu­lar front down­tube, lighter mud­guards and a larger fuel tank with chromed side pan­els. The sub­se­quent YD-3 was al­most iden­ti­cal ex­cept for slightly larger brakes and white-wall tyres. This model is most no­table for be­ing the first to use the Yamaha tun­ing fork mo­tif on the tank badges. The YD-2 co­in­cided with the set­ting up of a dealer net­work in USA, with sep­a­rate dis­trib­u­tors on the East and West Coasts. As early as 1958, Cooper Mo­tors in Los An­gles in­de­pen­dently im­ported and distribute­d Yama­has, and be­came the West Coast dis­trib­u­tor when the Yamaha In­ter­na­tional Cor­po­ra­tion was es­tab­lished. In Amer­ica, the YD-1 was mar­keted as the Elec­tra with a re­tail price of $565.00. By com­par­i­son, a new twin-carb 175cc Puch sold for $440.00, a 250cc MZ for $570.00, and the 200cc Par­illa for $549.00. But Yamaha was just get­ting started, and re­ally raised the bar in the quar­ter-litre cat­e­gory with the sporty YDS-1 (ini­tially mar­keted as the 250S) of late 1959, with 18hp on tap at 7,500 rpm and the com­pany’s first five-speed gear­box. Yamaha claimed the YDS-1 was de­rived from the Catalina rac­ers, with a du­plex cradle frame, twin car­bu­ret­tors, 18-inch wheels and the 56 x 50 bore and stroke from the Asami ‘B’ racer. The ba­sic styling of the YDS-1 would be car­ried through to a suc­cess­ful range of high per­for­mance 250 twins that would dom­i­nate the seg­ment for the next decade.

Our thanks to OLD GOLD MO­TOR­CY­CLES (02) 4574 2885 for the op­por­tu­nity to pho­to­graph this ex­tremely rare mo­tor­cy­cle.

Adler in­flu­ence is ev­i­dent in the power unit.

Chopped mega­phone muf­flers and large rear brake drum.

Fat front hub with equally im­pres­sive mud­guard.

Switch below the clutch lever con­trolled head­light func­tion and turn in­di­ca­tors.

Twist­grip is Euro­pean style spi­ral op­er­a­tion with the throt­tle cable run­ning through the han­dle­bar.

Gear lever and kick­starter shafts are com­bined, as on many Euro­pean mod­els.

ABOVE A rare bird in­deed. FAR LEFT Speedo in­te­gral with head­light. LEFT Tun­ing fork mo­tif was sub­tly in­cluded on the petrol tank cap. BELOW LEFT Stan­dard fit­ment steer­ing damper.

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