Cycle News - Archive Issues - 1970's

way p ipe, easy sh ifting transmission, predic tabl e brakes , a soli d skid-plate , a bucketful of low-end grunt, pr operl y spaced gear ratios, a good silencer, bear trap footpegs , indestructibility , and lightweight and unobtrusive, yet functional lights. The Yamaha has all of them, and a personality of its own to booL If co m pared. to the other p opular trials machin es, the T Y Yamaha is most like th e MAR Ossa . The geo me tr y is similar, so is th e power. It 's a tad slower handling than th e Bultaco Sherpa T or Montesa COla, an d it has a ligh ter flywheel than ei t he r, pe rmitting more use of the throttle to neg otiate na sty sections. The less-than-aver age flywheel effect m akes the TY a better playbike th an most tri al ers, more quick Rs to play with, but rar ely is it a hindran ce to genuine trials work. Only wh en th e engine is called on to do some heavy pulling at extremely low RPM's, o r when a long, slick uphill is encountered does the rider wish for mo re rotating engine mass. Many seri o us trials riders will consider the ligh t flywheel a disadvan tage, so surely an accessory ho use or tw o will come up with a bulkier replacemen t , T he TK carburetor (very similar to Miku n i ) a llows excellent throttle resp on se and ru ns clean up to the m a x imum of God-knows- how-many R PM. J ust as importantly, the unit wo n't load up if the b ike is dropped. The thing starts easily, too. Japanese. Yamaha's Autolube oil injection system likely c on trib utes to the engine's clean-running characteristics, because at t he lo w Rs so critical to precise trials wo rk the engine is only getting eno ugh oil for sufficient lubrication instead of the full measure for any operating co ndi tion, as in a pre- mix system. While the suspension doesn 't seem as precisely da mped as t he European Betor and Telesco trials units, the difference will probably only be distinguished by veteran trials riders. Impact damping on both the fron t and rear sh o cks is excellent, but the forks are a bit too sproingy o n th e rebound. The springs may be at fault. You can really slam i nto an obstacle hard without bottoming the forks, so hard that y o u 'll be dabbing anyway . The five gears are well-spaced, with first being super low, second sort of low , third so -so, fourth getting faster, and fifth gear is for cruising between sections... rapidly . For really snotty going, we'd suggest a slightly lower o veral l ra tio, whic h can be achieved by ins ta lling a co un tershaf t sp ro cket o ne size smal ler than stock. The thing shifts like a Yamah a En d uro : clean, positive, tr us tworthily . Just for the record , the clutch is st ro ng, smooth, and easy to use , but you already know that about Yamahas. Both the front and rear brakes o n our test TY Yamaha were ab sol utely per fect for trials work. Not grabby, yet affording co nsiderable stopping power. However, the owner of another TY informs us th at his brakes are poor. Manufacturing tolerances? TY's brakes get wet too easy, and stay wet too long. S ta n d in g on t he pegs be came ext re me ly c o mfo rtable o nce we replaced the stock handlebars. But some of you w ill no doubt prefer th e stockers. Some people even like to p lay golf. The footpegs hold on to yo ur b o ot even when muddy , and the seat is placed right where your behind lands wh en you're tired of sta ndin g. On e of t he thankful aspects of th e TY is its light w eight ; 2 05 lbs, dry, ab o u t 21 5-220 when yo u get oil in every th ing and a fistful o f mud in each rim (th ey 're DID, but mud still st icks t o 'em ). Body weight shifts have a profou nd effec t on th e direct ion yo u're goi ng , and th e so n of a pup isn ' t hard to p ick up wh en you crash. A ll things bein g eq ua l, we don ' t th ink th e T Y will nego tiate tight trials sectio ns as we ll as, say, a Sh erpa, but th e Yamaha w ins p oints because it is a more fo rgiving ma chine than a Sherpa. It doe sn 't r equire br a in-flexing conc en tra tio n to rid e stylishly, thus m aking it m or e su it able for No vices. However, it is the super precise s tee ring that makes the Spanish trialers th e 100% no no nsense machi nes that th ey arc. Brain-flexing concentration wins fI.I 51 IiI:lI • IiI:lI ~ g ~ g ~ r0- C"> l!"l >::':l ::: c: :':l ~ tria ls even ts . As we spent mo re ti me in the saddle of the TY, we began to wish it had enduro accoutrements. Not because trials riding isn't the Yamaha's bag, but sim ply because the bike wo uld also make a fine Alpina-type m achin e. With different bars, seat and footpeg placemen t , the Yamaha Trials would be superb for the kind of en duros you'll find anywhere east of California. You co uld probably even learn to live with the bike on the streets, after adding the hom and mirror necessary to meet most Andrews' prototype featured a Mikuni carb and a shift lever that was more accessible and could be ad justed. The production model didn't and proved harder to live with. Both versions have cha in tensioner, oiler and Autolube with a swingout oil t ank, Yamaha should have listened to Mick the whole way . states' legal req uire me n ts. The TY -25 0 c o mes from the cra te with everything necessary to win tri als events, but like every other type of single purpose co mp eti tio n bike it may req uire some fine tuning to sui t yo ur style. As we see it, the main problem with the bike is th at everybody's go ing to have one, which does little to gra tiate trails riders' innate desire to be different. Go buy a Sammy Miller hat. Plastic bash plate hides no frame un der engine. Silence r is vul nerable t o endos. Specif ications M in . Turn ing radius Min. Brak ing distance ENG IN E 53 .0 in . 49 2 ft. @ 31 mp h Type . . . . .2-stroke. To rque Induc tio n. Single D ispl acement Bore X Stroke Compression ratio Max . torque Lubricati on system 246cc (15.0t eu. in.) 2 .766x2.520 in. N .A . 15 2 ft . Ib . @ 5,5 00 rpm A utolu be Starting system Primary kick starter Ignit ion sy stem Flywheel Magneto Transmissio n D IM ENSIONS Overa lt lenqth Overa ll width O""rall height Wheelbase 5 -speed gearbox 78 .1 32 .9 43 .7 5 1.0 112 ... in . in . in . in . in. Min . ground clearance FUEL TANK Capacity 1.59 U.S. gal. TIR ES Fron t 2 .75 ·214 PR Rear .. . .. . ... . ...... . . . • .4.00xI8 .4 PR (He didn't see the hill) *%!X+%t !*%X! Hold her down Hog Body wh ile I get back on and wh eelie off int o th e sun set:' A happy end ing no doubt. 35 -

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