Clas­sic Ma­chine

Classic Trial - - CONTENTS -

Yamaha TY 250cc

The early seven­ties wit­nessed an in­cred­i­ble in­ter­est in one-day tri­als and off-road rid­ing in gen­eral. Not just in Europe but also around the globe in Aus­tralia, Amer­ica, Canada and Ja­pan. This gave Ossa works rider Mick An­drews and his wife Jill the chance to tour Amer­ica, where they made many friends. The 1973 In­ter­na­tional Six Days Trial was due to run in Amer­ica so Mick and Ossa went over in 1972 to prac­tise and also set out on a pro­mo­tional tour to help cre­ate some much needed sales for Ossa ma­chines. At the time Ossa were go­ing through a rough patch due to many fi­nan­cial prob­lems. Whilst prac­tis­ing with Amer­i­can ‘Ossa Yan­kee’ rider Barry Hig­gins Mick had a se­ri­ous crash and badly sep­a­rated his shoul­der. The prog­no­sis, af­ter two op­er­a­tions, meant no se­ri­ous mo­tor­cy­cling for a six-month pe­riod. It was dur­ing this pe­riod of re­cu­per­a­tion that Yamaha first made con­tact with Mick – in re­ally bizarre cir­cum­stances. He was eat­ing in a restau­rant at Los Angeles air­port when a tan­noy an­nounce­ment was made for Mick to go to a re­cep­tion desk to take a tele­phone call. He took the phone call, and it was from Yamaha road-racer turned team man­ager Rod Gould. This was the start of a new chap­ter in the life of Mick An­drews. Words: John Hulme Pic­tures: Eric Kitchen, Yamaha, Doug Jack­son, Mor­ton’s Ar­chive and Yoomee Ar­chive

Gould was well aware of An­drews’ de­vel­op­ment ca­pa­bil­i­ties, hav­ing wit­nessed his work first hand with the Ossa project. Yamaha wanted the top rid­ers on their ma­chines and Gould’s job was to hire An­drews. He asked if he would be in­ter­ested in de­vel­op­ing a tri­als ma­chine for Yamaha in Ja­pan. You must re­mem­ber, around that time Sammy Miller had moved from Bul­taco to Honda, Don Smith from his pri­vately owner Mon­tesa pow­ered ‘Stag’ to Kawasaki and Gor­don Far­ley from Mon­tesa to Suzuki. The tide had turned on the Span­ish tri­als ma­chines and was now head­ing to the Land of the Ris­ing Sun, Ja­pan.

On his re­turn home and af­ter giv­ing the idea a great deal of thought Mick de­cided to re­turn their call with an an­swer. A deal was struck and he be­came the Ja­panese fac­tory’s first works tri­als rider. The new 250cc pro­duc­tion ma­chine was nearly ready in Ja­pan but they waited for An­drews to make his sug­ges­tions on how to im­prove the ma­chine. He sug­gested some changes to the mo­tor and the chas­sis, us­ing his knowl­edge and ex­pe­ri­ence to fine­tune the new pro­duc­tion model.

Af­ter many hours spent in Ja­pan his new ‘works’ ma­chine ar­rived in Fe­bru­ary 1973, along with a Ja­panese en­gi­neer to help An­drews de­velop his ideas which were to be in­cor­po­rated into the pro­duc­tion ma­chine. They spent many hours at his home prac­tice area at Bur­rycliff El­ton, in Der­byshire, on the ma­chine but it still needed much work.

It was ru­moured to have an en­gine size of 360cc. Mick gave the ma­chine a tough bap­tism though — in the open­ing round of the Euro­pean cham­pi­onship held just out­side Barcelona, near the home of Ossa — and the Span­ish fans were not happy! An­drews had a tough time with the crowd but still came home in sev­enth po­si­tion.

Not one to be in­tim­i­dated though he took sweet re­venge two weeks later when he won the French round of the Euro­pean cham­pi­onship.

His next tar­get would be the Scot­tish Six Days Trial, an event he had taken a hat-trick of wins in from 1970–1972. Could he be­come the first rider in the long his­tory of the event to take four wins in a row?

Dur­ing the six days of the event based around Fort Wil­liam he was up and down the leader board. He fin­ished day two in third po­si­tion, day three in sixth po­si­tion then moved into the lead on day four be­fore slip­ping to sec­ond, where he even­tu­ally fin­ished, just be­hind the win­ner Mal­colm Rath­mell. An­drews had been un­lucky not to win but had proved to Yamaha the po­ten­tial of the new ma­chine.

It was the same story in the Euro­pean cham­pi­onship where he was aim­ing for an un­prece­dented hat-trick. He fin­ished run­ner- up but he had used the cham­pi­onship to help de­velop the works ma­chine.

An­drews had a few small, in­signif­i­cant, dis­agree­ments with his de­vel­op­ment team con­cern­ing the pro­duc­tion ma­chine, when the com­puter did not agree with his ideas, but it was so close to be­ing ready to be re­leased to the pub­lic. Happy with de­vel­op­ments the Yamaha team in Ja­pan pressed the but­ton and the as­sem­bly-line wheels be­gan to turn out the TY 250cc in sum­mer 1973.

Pro­duc­tion

The of­fi­cial in­tro­duc­tion of the new model was on the 3rd Au­gust. It looked su­perb with its sil­ver frame and yel­low-and-white colour scheme. The en­gine had been thor­oughly de­signed and con­structed for very low-speed per­for­mance. The ‘Torque In­duc­tion’ en­gine was ideal for this low-speed oper­a­tion since its pri­mary char­ac­ter­is­tic was to de­velop more torque over the lower and mid­dle speed ranges. The reed valve and seven port cylin­der de­sign would aid scav­eng­ing ef­fi­ciency and there­fore im­prove the im­por­tant throt­tle re­sponse, giv­ing the rider a more pos­i­tive feel­ing of the ma­chine’s per­for­mance. The pis­ton used an ‘L-Type Key­stone Ring’ as it yields a bet­ter seal­ing char­ac­ter­is­tic.

When the tri­als ma­chine is op­er­ated hard at low speeds the en­gine will be­come rather hot caus­ing ex­pan­sion to oc­cur, thereby re­duc­ing com­pres­sion; this Key­stone-type pis­ton of­fers a bet­ter ap­pli­ca­tion for the tri­als mo­tor.

The crank and fly­wheel mag­neto sys­tem were also dif­fer­ent from those cur­rently found on the tri­als ma­chines, in that a large ro­tat­ing mass was re­quired or the mo­tor would stall at low speeds; how­ever the mass must also be light enough to of­fer a rapid throt­tle re­sponse time. With these re­quire­ments as a guide the op­ti­mum weight and de­sign for the crank and fly­wheel were selected.

The gear box was a five-speed unit with the first three gears aimed at tri­als use and the other two for higher speeds when trav­el­ling around the course.

And the ic­ing on the cake was the fact that, over its Span­ish ri­val ma­chines, the Yamaha could be started with the ma­chine still en­gaged in gear.

An­other first on a tri­als ma­chine was the use of an ‘Au­tol­ube’ sys­tem, us­ing a sep­a­rate oil tank from the fuel which mixed the two to­gether mean­ing the rider did not have to pre-mix the fuel be­fore putting it in the tank.

The qual­ity of the other com­po­nents was ex­cel­lent and en­hanced the ma­chine’s tri­als looks. The wheel hubs were far su­pe­rior to the Span­ish ma­chines and they had a unique seal­ing sys­tem for the brake cham­ber to help keep the brake shoes dry.

Many com­po­nents were made from alu­minium and mag­ne­sium to help re­duce the over­all weight.

The front forks pro­vided ex­cel­lent sus­pen­sion, pro­vid­ing a long cush­ion-stroke, which also gave ex­tra rigid­ity and in turn en­sured a more ef­fi­cient and last­ing damper ac­tion. It was the same at the rear as the chrome-fin­ished shock ab­sorbers were multi ad­justable.

Also in­cor­po­rated in the rear swing­ing arm was a chain oiler to keep the chain lu­bri­cated at all times and a rear-fac­ing chain ten­sioner. The new ma­chine had lived up to all ex­pec­ta­tions, and all they had to do now was sell them.

The en­gines de­sign was purely for tri­als and in­cluded Torque In­duc­tion – Au­tol­ube – Key­stone ‘L’ type pis­ton ring Mick and Jill An­drews had a fan­tas­tic time pro­mot­ing the new ma­chine around

the globe

Mick and Jill An­drews even fea­tured in the pro­mo­tional brochures for Yamaha

Can­tilever Shocker

As soon as the sea­son was over An­drews went straight to Ja­pan to dis­cuss de­vel­op­ments of his 1974 works ma­chine be­fore trav­el­ling to Aus­tralia on a pro­mo­tional tour to pro­mote the new Yamaha TY 250cc.

Mick and Jill had a fan­tas­tic time, as the mo­tor­cy­cling pub­lic loved to see Mick per­form on the new Ja­panese ma­chine. Yamaha also used this time to make many pro­mo­tional and mar­ket­ing films and brochures fea­tur­ing their new ma­chine.

Dur­ing the lat­ter part of the tri­als sea­son in 1973 An­drews had started to use a 250cc cylin­der on his ma­chine af­ter ini­tially test­ing with the 360cc. Yamaha were promis­ing some­thing spe­cial in the way of a new 250cc for the 1974 sea­son but when it ar­rived in the UK it blew even the usu­ally calm An­drews away!

It was Fe­bru­ary and the weather was cold but this new Yamaha was the hottest property on the tri­als scene in gen­er­a­tions.

The Yamaha Mo­tocross team had suc­cess­fully in­tro­duced the ‘Can­tilever’ sin­gleshock frame in 1973, de­signed by Bel­gian en­gi­neer Lu­cien Tilkins, and it was also suc­cess­fully adapted for the road rac­ing team, so why not tri­als? The new ma­chine was rad­i­cal to say the least, on looks alone. With no rear shock ab­sorbers vis­i­ble the whole of the rear sub frame piv­oted from

its low­est point, and the rear wheel was car­ried at a sep­a­rate apex be­fore a third con­tact point con­nected with the sin­gle large-ca­pac­ity gas filled shock ab­sorber. This sin­gle unit ran up un­der the fuel tank to a lo­ca­tion point be­hind the steer­ing head­stock. This idea was sup­posed to al­low for more rear wheel travel and also adapt bet­ter to weight trans­fer sit­u­a­tions by the rider.

Var­i­ous other com­po­nents on the ma­chine were new but even more was to come. At first the ma­chine used a con­ven­tional car­bu­ret­tor but, less than a month later, this was swopped to a form of fuel in­jec­tion. This was a con­ven­tional look­ing Mikuni branded car­bu­ret­tor but the float bowl was re­placed by what looked like a block of rub­ber. It was in fact the ‘brains’ of the new con­cept of fuel in­jec­tion which had a tube con­nect­ing it to the crankcases, which in turn pumped fuel us­ing the pres­sure gen­er­ated to con­trol the fuel sup­ply. An­drews loved the ma­chine and it also demon­strated Yamaha’s com­mit­ment to its fu­ture in tri­als.

SSDT Win­ner

Mick was full of enthusiasm for the new ma­chine and when he won the 1974 Scot­tish Six Days Trial on it he gave Yamaha the priv­i­lege of hav­ing the first ever win by a Ja­panese ma­chine in this pres­ti­gious event. He would also give a Ja­panese mo­tor­cy­cle man­u­fac­turer its first win in the world tri­als cham­pi­onship when he won the Bel­gian round on his way to third over­all in the se­ries.

Back in Ja­pan they were get­ting ready to make changes to the pro­duc­tion ma­chine for its launch in 1975, hav­ing learnt so much from the de­vel­op­ment work car­ried out by An­drews and his team with the works ma­chine.

They moved back to twin rear shock ab­sorbers and a con­ven­tional swing­ing arm for an­other win for Mick An­drews at the SSDT in 1975, hav­ing learnt all they needed to know from the ‘Can­tilever’ ma­chine. The red-and­white fuel tank car­ried on the works ma­chine was car­ried over to the new pro­duc­tion ma­chine in 1975.

Other changes were made to en­gine in­ter­nals and new, nar­rower, clutch and mag­neto cases were fit­ted. A new cylin­der bar­rel ap­peared and the seat’s de­sign was also changed.

The new ma­chines looked good but the buy­ing pub­lic did not take to them. They were more ex­pen­sive than the Span­ish ma­chines from Bul­taco, Mon­tesa and Ossa. They also wanted a ma­chine that per­formed the same as the one Mick An­drews com­peted on and did not see the at­trac­tion of the pro­duc­tion TY 250cc, which they con­sid­ered in­fe­rior to the one An­drews had. The pro­duc­tion ma­chines were sold world­wide with only mi­nor cos­metic changes such as the fuel tank colours and trans­fer de­signs.

At the end of 1975 the de­vel­op­ment pro­gramme was over, hav­ing run its three year term with An­drews, and Yamaha Ja­pan pulled the plug on the de­vel­op­ment pro­gramme in Ja­pan.

Mick signed to ride for the Dutch Yamaha im­porters and moved to Hol­land, where he con­tin­ued for a pe­riod of time still rid­ing vari­ants of the Yamaha tri­als ma­chine in all the ma­jor tri­als com­pe­ti­tions.

In 1978 pro­duc­tion of the Yamaha TY 250cc was over even though ma­chines would still be sold right up un­til 1981, but as this era came to an end a new one started with fur­ther pri­vate de­vel­op­ment of the ma­chines, and we would see Yamaha pow­ered Majesty and White­hawk ma­chines us­ing the TY 250cc en­gine.

Mick An­drews be­came in­volved with long-time friend John Shirt, and the Majesty project was born putting him back on a Ja­panese en­gined ma­chine.

The ini­tials Mick An­drews John Ed­ward Shirt Tri­als Yamaha was the ti­tle given to the new Yamaha con­verted tri­als ma­chine that John and Mick de­vel­oped, with the 320cc ver­sion of the ma­chine win­ning the 1980 Bri­tish World Cham­pi­onship round.

In the March of 1973 Mick An­drews was be­gin­ning to de­velop the leg­endary TY range in UK na­tion­als 1973 SSDT: This ma­chine he rode in the

‘Scot­tish’ fea­tured many changes.

The first pro­duc­tion TY 250cc

An­drews in ac­tion of the TY 250cc

1975 SSDT: Nick Jef­feries rode one of the very first pro­duc­tion TY 250cc Yamaha ma­chines in 1974 and stayed on the ma­chines dur­ing 1975 1974: Mick An­drews be­came the rider to give a Ja­panese

com­pany its first SSDT win on the Yamaha 1974: Mick An­drews rides out on the new

‘Can­tilever’ sin­gle shock ma­chine

1975 SSDT: It was an­other win for Mick An­drews on the Yamaha The 1975 pro­duc­tion ma­chine fea­tured new slim­mer en­gine cases and some other mi­nor changes

1975 North­ern Ex­perts: Wal­ter Bul­lock com­peted on a Yamaha TY250cc out­fit with sup­port from Mick An­drews 1976: Mick An­drews on the full road le­gal TY 250cc in this pro­mo­tional pic­ture 1976: The TY 250D had more mi­nor changes made to it

1976 SSDT: It was not to be three wins in a row for Mick

An­drews as he fin­ished 7th rid­ing with a bro­ken foot 1976: This is the Amer­i­can mar­ket ver­sion of the TY 250cc car­ry­ing a blue colour scheme 1977: This is the Amer­i­can mar­ket ver­sion of the TY 250cc car­ry­ing yet an­other blue colour scheme 1977: This was the Euro­pean

ver­sion of the TY 250cc

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