Pit­man’s XS11

Chain-drive rocket

Old Bike Australasia - - NEWS - Story Pho­tos Jim Scays­brook John Ford, Keith Muir, Rob Lewis, Sue Scays­brook, Mal Pit­man

The shaft drive XS11 Yamaha was never con­ceived as a race bike, but that didn’t stop it win­ning count­less Pro­duc­tion races from 1978 – at a time when the Un­lim­ited Pro­duc­tion class was the hottest and most fe­ro­ciously-con­tested event on most pro­grammes.

But the nascent

Su­per­bike cat­e­gory was an­other thing al­to­gether – the do­main of home-brewed rock­ets like the Syn­di­cate Kawasaki and the Hone Suzukis, par­tic­u­larly in the NGK-spon­sored Vic­to­rian Su­per­bike Cham­pi­onship which mor­phed into the na­tional ti­tle in a few short years. In this class, the XS11 was sim­ply off-spec – the shaft sys­tem too heavy and the ma­chine it­self un­gainly. How­ever over the sum­mer of 1980/81, Yamaha Pit­mans in Ade­laide – a dis­trib­u­tor with close ties to the fac­tory in Ja­pan – de­cided to rec­tify the sit­u­a­tion. In Greg Pretty, their con­tracted rider, they had a man of out­stand­ing abil­ity and de­ter­mi­na­tion, who weighed just 53 kg, just what was needed to make the portly XS1100 com­pet­i­tive in Su­per­bike trim. But there were other is­sues… To start at the be­gin­ning, Yamaha had re­treated into its shell fol­low­ing con­sec­u­tive dis­as­ters with the twin cylin­der TX750 – the com­pany’s first four stroke – and the TX500 – its first twin cam de­sign, and had guard­edly pre­pared to rec­tify the sit­u­a­tion (and its badly tar­nished im­age) with its first four­cylin­der four stroke. This was the XS1100 (or XS 1.1 in USA) that broke cover in late 1977, de­signed first and fore­most as a lux­ury tourer. That is, un­til Yamaha Pit­mans got hold of it. Mal Pit­man, the tech­ni­cal chief of the com­pany’s rac­ing ef­forts, ex­plains the process that ul­ti­mately re­sulted in the XS1100 Su­per­bike. “In De­cem­ber 1977 Yamaha brought a crew of a tech­ni­cian and three rid­ers from Ja­pan, and we tested the bikes in the east­ern area of South Aus­tralia; we went up and down the bor­der with Vic­to­ria, 650km rides each day. They wanted us to do over 180km/h all the time, so they could check the dura­bil­ity of the en­gine. This was the mid­dle of sum­mer, 40 de­grees am­bi­ent with the road tem­per­a­ture up around 60. The rear tyres were last­ing 650 km and they were shred­ded. We ba­si­cally brought all the 17 inch tyres we could find in Ade­laide. “We had a good rider in Greg Pretty – he was one of the guys that tested the sus­pen­sion with us – but he wasn’t fa­mil­iar with the XS1100 and had al­ways rid­den Kawasaki 900s. On the first day he went into a cor­ner two fast, and not be­ing fa­mil­iar with the XS11, shut the throt­tle and down he went, decked the bike. When you close the throt­tle on a shaft drive in the mid­dle of a cor­ner, the bot­tom drops. When he crashed that bike, the Ja­panese re­ally wanted to know if their rollover sen­sor, or tilt an­gle sen­sor, had worked, and had cut the en­gine. So tongue in cheek I told them that when I got to the bike, it was stopped. It was also in sev­eral pieces as well! So he learned how to ride the bike and when he went onto Pro­duc­tion Rac­ing, he won every­thing, but the Su­per­bike was some­thing he re­ally wanted to ride be­cause they had more horse­power and he was a horse­power nut.” Pretty and the XS1100 in­stantly be­came the ma­jor force in the 1978 Pro­duc­tion Rac­ing sea­son, win­ning the pres­ti­gious Ad­ver­tiser Three Hour in April, and two weeks later, the Perth Four Hour, this time paired with Mick Cole. In Septem­ber, Pretty took out the Surfers Par­adise Three Hour, the tra­di­tional cur­tain raiser to the ‘big one’ the Cas­trol Six Hour at Ama­roo Park. Teamed with Jeff Miller, Pretty’s Pit­man’s team looked a shoe-in for the Six Hour, and led the race un­til Miller crashed the bike and put it out. Although dev­as­tated, the Pit­mans team shifted their at­ten­tion to help­ing the Avon Tyres squad, which was also run­ning and XS1100 for Jim Budd and Roger Heyes. Be­tween them, they pulled off a mas­ter stroke by chang­ing the rear wheel at half dis­tance and won the race. The amaz­ing Pretty com­menced the 1979 sea­son where he had left off in 1978, win­ning the Ad­ver­tiser Three Hour again (and cov­er­ing five more laps than the pre­vi­ous year, on the same bike), then snatched the Perth Four Hour, part­nered this time by Jeff Parkin. Teamed with 1978 win­ner Jim Budd, pretty and the Pit­mans XS1100 again went into the Cas­trol Six Hour as firm favourites, but lost out to the Suzuki GS1000 of Alan Hales/Neil Chivas, who went through the race on one set of Pirelli tyres, while the Pit­mans Yama­has needed a rear wheel change and fin­ished sec­ond, three laps in ar­rears. Pretty de­cided to try his hand in Europe in 1980, so the Pit­mans squad re­mained largely un­der wraps. The face of rac­ing in Aus­tralia was chang­ing too, with the big, bel­low­ing and spec­tac­u­lar Su­per­bikes – largely home-brewed spe­cials – emerg­ing as the next big thing over the tra­di­tional grand prix classes. When Pretty re­turned and faced the prospect of spend­ing the 1981 sea­son at home, he wanted to be part of that scene too. His prob­lem was that Pit­mans, and Yamaha, had noth­ing suit­able for the class. Or did they? Mal Pit­man was one per­son who was con­vinced that the XS1100 could be made com­pet­i­tive in the Su­per­bike class – but with one ma­jor mod­i­fi­ca­tion. “Be­cause of (our ex­pe­ri­ence with the model) and our con­nec­tion to the fac­tory, Yamaha de­cided to make some fac­tory en­gine kits for the XS1100 to al­low them to go Su­per­bike rac­ing. Un­for­tu­nately they felt the shaft drive was suit­able for Su­per­bike rac­ing, and I didn’t think it was, so they for­warded the bits to my fa­ther and un­cles who ran Yamaha Pit­mans and said they’d re­ally like us to build a Su­per­bike. My un­cles ba­si­cally told them what I’d said; that shaft drive was a waste of time. But they said, ‘you have to build it for us be­cause we want to get the cov­er­age’, so I elected to mod­ify the bike to turn it into a chain drive XS11, and once I’d done that it made the kit come to life be­cause you had less weight, you could change the gear­ing, and so then we were able to get rac­ing. I had a lo­cal guy who loved bikes, was a ma­chin­ist and dab­bled with cast­ing, and I showed him the prob­lem

“Pretty and the XS1100 in­stantly be­came the ma­jor force in the 1978 Pro­duc­tion Rac­ing sea­son, win­ning the pres­ti­gious Ad­ver­tiser Three Hour in April, and two weeks later, the Perth Four Hour, this time paired with Mick Cole.”

we had with the right an­gle drive. We worked out that the shaft in­side the right an­gle drive had the same spline as a TZ750 sprocket, so we pro­ceeded to pull the shaft apart, cut the box up, we made an ex­ten­sion off the gear cover on the left hand side so it had an out­rig­ger bear­ing, so we used the orig­i­nal shaft with two new hous­ings and that gave us the sprocket on the en­gine. Then I had to build a swing arm for it that was wide enough, be­cause we had to run the sprocket very wide, to miss the gear­box. That was made out of chrome moly, su­per strong, and we then ran TZ Dy­mag mag­ne­sium wheels – or the spoked wheels, de­pend­ing on the weather. The rear shocks are the alu­minium body and finned Koni 76V shocks, 5-po­si­tion ad­justable in­ter­nally, which you did by tak­ing the spring off and push­ing the shaft to the bot­tom to ad­just the in­ter­nal damp­ing mech­a­nism for re­bound and com­pres­sion.

“It (the fac­tory kit) was a very com­pre­hen­sive kit. Crank­shaft, con rods, pis­tons, a twin-plug head, camshafts, ex­haust sys­tem, car­bu­ret­tors, hy­draulic clutch, clutch springs, mag­ne­sium oil fil­ter cover. The twin plug head Yamaha partly made with their Toy­ota 2000GT tech­nol­ogy. It was an all-new head with 10mm plugs, the orig­i­nal plug was 14mm. Two plugs were side by side but you had to run each from a dif­fer­ent ig­ni­tion sys­tem. They sup­plied side draft Mikuni/Solex carbs, 40mm, sleeved back to 36 with the ef­fec­tive ven­turi 34mm. They had big long bell mouths, and long in­takes like a 6 or 4 cylin­der car, un­der-bucket shims in the head. I ran 11.5:1 com­pres­sion, 100 oc­tane fuel, two base gas­kets to get the cor­rect com­pres­sion, XJ650 ig­ni­tion as per fac­tory spec. For Oran Park and Bathurst we had a small sin­gle phase gen­er­a­tor on it with to­tal loss for the last race. The race crank was a cou­ple of kg lighter, with spe­cial con rods, and big­ger con rod bolts. Forged high comp pis­tons, very thin 1mm com­pres­sion rings, stan­dard oil rings. The kit came with Mikuni/Solex We­ber style carbs, they worked quite well but the bike was very hard to start. I didn’t want to run them be­cause on that type of carb the float runs side to side so when you turn a left cor­ner it leans off and when you turn a right cor­ner it richens up. For me that was a big prob­lem but Greg was happy to run that at Bathurst and we had no prob­lems. Be­cause we were run­ning a TZ750 coun­ter­shaft sprocket we had to change the mid­dle gear (pri­mary?) so Yamaha cal­cu­lated what we needed and made me a set of new mid­dle gears, I told them first gear was too low so they made me a high ra­tio first gear to make the gear­box a bit closer, but apart from that the gear­box was stan­dard. Part of the fac­tory kit was a big­ger oil cooler. It got very hot if you idled it but in op­er­a­tion it was OK. It was still 1100cc stan­dard so had plenty of fin area. Brakes had to be stan­dard from the era, but in the day Yamaha brakes were the pre­ferred brakes be­cause they were 300mm, Suzuki and Kawasaki were only 280. They’re ter­ri­ble now but in the day, they worked very well.

“We had planned to race the Su­per­bike at the Coca Cola 800 at Oran Park, which was an 8 Hour race in Fe­bru­ary 1981. We were still build­ing the bike as we were trav­el­ling to Syd­ney be­cause it was such a big un­der­tak­ing. Gary Coleman was the co rider. On the first day, he jumped on and did half a dozen laps and came in and said, “We’re go­ing to win the race, no prob­lem’. I didn’t be­lieve him but he was quite sure. Then it rained and we won the race by seven laps, but Gary said the bike was so rider-friendly and easy to ride that we just walked away. “We then de­cided we would run at Bathurst in April, so we had a TZ750, TZ500 and the XS1100 for Greg to ride. Un­for­tu­nately at Bathurst there was only one prac­tice ses­sion for all those bikes, so Greg had to go out and do two laps on one, come in, two laps on the next one and so on. It was the first time we had run the TZ500 and I hadn’t had a chance to do the jet­ting on it and it was jet­ted way too rich and even though I put 30 litres of fuel in it he ran out of fuel on the last lap when he was sec­ond. But he won on the 750 and in the Arai 500 he rode the XS and won by about a lap and that be­came folk­lore be­cause it was a leg­endary bike that had a 100% win­ning record.” All change That could have been the end of the story for the chain-drive XS1100, but Yamaha Pit­mans al­lowed Pretty to take it to Win­ton in Vic­to­ria for the open­ing round of the NGK Su­per­bike Se­ries in May 1981, along with a me­chanic. How­ever Pretty failed to make it to the grid af­ter stepping off the Yamaha dur­ing prac­tice, dam­ag­ing it too ex­ten­sively to make the race. The bike went back to Ade­laide with im­me­di­ate plans for a fur­ther out­ing. That mat­ter was set­tled when Pretty dropped a bomb­shell by tak­ing up an of­fer to join Team Honda, whose lead rider Dennis Neill had suf­fered ca­reer-end­ing in­juries at Bathurst. It was a move that floored Pit­mans, and se­verely cooled their en­thu­si­asm for rac­ing. In fact, it was just a fur­ther el­e­ment in a chain of events that would change the com­pany’s tra­di­tional busi­ness role, as Mal Pit­man ex­plains. “So we lost Greg, and the next year the gov­ern­ment de­val­ued the Aus­tralian dol­lar. We were im­porters so the fam­ily busi­ness de­cided we had to get rid of our race bikes, so they were all sold off. I had a guy, Colin Dy­mock, who used to come through each year when he was on hol­i­days and he would al­ways ask me if he could buy the XS1100 Su­per­bike. I said it wasn’t for sale but about the third or fourth time he came through I said I’d sell it to him. He had eleven XS1100s so he had se­ri­ous is­sues! He took it away and gave me his phone num­bers at home and at work and I said if you ever want to sell it let me know. I rang up about five or six years later but both num­bers had changed, so I lost con­tact and the bike ba­si­cally dis­ap­peared for about 35 years, but he never told any­one he had it. “Then John Te­store, who had worked for the NSW Yamaha dis­trib­u­tors, McCul­loch and used to ser­vice Colin’s XS1100s, was talk­ing to him. Colin had be­come quite ill and was hav­ing trou­ble walk­ing, so he took John down to his gar­den shed and said to him, ‘I’ve got the Yamaha Pit­mans XS1100 chain­drive’, and John said ‘no way’, so he told him to go into the shed and look for him­self. Un­for­tu­nately the roof had fallen in on the shed so the bike was badly weath­ered, but John knew straight away what it was and bought it from Colin and promptly rang me up and told me had had the bike. I kept that in the back of my mind and I was pretty keen to buy it be­cause I’d al­ways wanted to own it from back in the day. “Then in De­cem­ber 2017 PCRC rang me up and said they were hav­ing this 30 Years Cel­e­bra­tion of Su­per­bikes at the In­ter­na­tional Fes­ti­val of Speed in March and could you bring the chain-drive XS? So I rang John and he said ‘I was go­ing to ring you, I am pretty keen to get the thing re­stored’. So he brought the bike to the Aus­tralian His­toric ti­tles in 2017 at Goul­burn and I took it back to Ade­laide and got to work on the bike. It was a very tight sched­ule; it was only fin­ished on the Tues­day of the week of IFoS. It’s not com­pletely fin­ished to my sat­is­fac­tion but it has come up very nice although the car­bu­ra­tion needs sort­ing out. A rapid restora­tion With scarcely three months to com­pletely re­store the bike, Mal Pit­man had his work cut out, but de­spite the bike’s en­forced hi­ber­na­tion, the task was not quite as daunt­ing as it could have been. “The ex­haust valves were stuck open and two of the

pis­tons had some mois­ture dam­age but I was able to get CRC into the mo­tor and move it backwards and for­wards un­til I could get it to turn over. I wanted to check the cam tim­ing just to re­fresh my mem­ory. So I pulled it all apart and it was still in re­ally good or­der in­side. I re­placed all the main bear­ings and big end bear­ings, honed the bores, ran the same pis­tons and rings be­cause they were in good or­der, cleaned the valves and re­cut the seats, re-shimmed it, put a brand new set of Kei­hin CR33 smooth bore carbs on it, fired it up and she ran sweet as. It was John Te­store’s de­ci­sion to fit the Kei­hins, but the orig­i­nal Solex/Mikuni carbs were badly cor­roded and would have taken a lot of work to get them back into work­ing or­der – more time than we had.

“I know the guy at the lo­cal trade school so I put it on their dyno. This was the Tues­day night be­fore IFoS and we had to leave at 3am on Wed­nes­day morn­ing.He said it was a bit lean at idle, too rich in the bot­tom range, nice at three-quar­ter throt­tle and prob­a­bly a jet size out on the main jet. He said the torque curve is a flat line; it’s in­cred­i­ble how much torque it’s got. It was show­ing 108kW, or about 144 horse­power, and that blew me away be­cause we al­ways thought it was about 120 horse­power, but in those days we didn’t have dynos – we’d just ride it and see how it went. We were pretty im­pressed back then be­cause it was as fast as Rob­bie Phillis’ GSX1100 and as fast as the CB1100R that Dennis Neill rode, which had a fac­tory Honda RC kit on it. But Honda and Suzuki Yoshimura had all the ex­pe­ri­ence whereas Yamaha had no four stroke ex­pe­ri­ence. The next model they brought out was the FJ1100 which chas­sis wise were not great but the mo­tors were bul­let­proof and great for mak­ing horse­power, and from there to the FZR1000. So this bike was the stepping stone and prob­a­bly the first Su­per­bike from Yamaha any­where in the world. I know So­nauto had the Fior one (also chain drive which raced at the Bol d’Or) which had the same race kit on it but we ba­si­cally raced ours as a full Su­per­bike. All the cy­cle parts are stan­dard – heavy steel fuel tank. I reckon the bike now is around 200 kilos and I think it could lose an­other 15kg by do­ing lots of lit­tle stuff. A quick squirt At Syd­ney Mo­tor Sport Park, I was able to get a run on the XS1100 dur­ing one of the IFoS Leg­ends ses­sions. Af­ter do­ing the ear­lier ses­sion on Mur­ray Kahler’s NCR Du­cati that I had raced in the 1978 TT, jump­ing onto the Yamaha was quite a con­trast; one low and long, and the other bike high, wide and hand­some. Mal Pit­man’s son in law Nathaniel Wil­son had taken the Yamaha out for a shake down run and re­ported fluffy car­bu­ra­tion, so there was a quick hunt through the pits for al­ter­na­tive jet­ting prior to my ride. This went part of the way to cur­ing the prob­lem but Mal says he’s still not en­tirely happy with it, although con­sid­er­ing the short space of time he had to com­plete the work, it’s a job very well done. Look at the pe­riod pho­tos of Greg Pretty and you will see a lit­tle bloke on a big bike. The power-toweight ra­tio was very good. When I hopped aboard the XS I was im­me­di­ately struck with the sheer pres­ence of the ma­chine. It’s not just that it is phys­i­cally large, but the styling, es­pe­cially the fuel tank, make it ap­pear that way. Nev­er­the­less, once you’re un­der­way this im­pres­sion dis­ap­pears. What takes over is the stonk­ing mid-range surge of power, and the over­all per­for­mance pack­age which, for a ma­chine orig­i­nally con­ceived over 40 years ago, is mighty im­pres­sive. From my lofty perch it seemed a long way down to the track, but the XS steers per­fectly, and even though I had been pre-warned about the ef­fi­ciency of the brakes, I found very lit­tle lack­ing there. I def­i­nitely agree with Mal that Yamaha had the pick of the brakes back then; even my own 1973 TX750 with its sin­gle disc, twin pis­ton caliper stopped quite ad­e­quately, and I never had any com­plaints about the range of TZ350s, sim­i­larly equipped, that I raced in pe­riod. You do no­tice the weight, no ques­tion, par­tic­u­larly at the down­hill hair­pin at SMSP, where the force of grav­ity, cou­pled with a tight, de­creas­ing ra­dius cor­ner, makes chang­ing di­rec­tion a con­sid­ered ex­er­cise. But then comes the good bit, ac­cel­er­at­ing away to­wards Turn 11 and the Yamaha fairly bolts, with plenty of time be­tween gear changes to savour the ex­pe­ri­ence. As Mal says, the car­bu­ra­tion is not yet spot-on, but it’s not all that bad ei­ther. Hey, let’s put the Solex/Miku­nis back on and try that!

It would be an in­ter­est­ing ex­er­cise if Mal could in­deed re­move an­other 15kg, but in a way, I hope he doesn’t. Here is a time-warm mo­tor­cy­cle, pretty much ex­actly as it was raced in 1981. Even the paint­work is orig­i­nal. Yes, true – it only re­quired buff­ing, even af­ter all those years semi-sub­merged in the leaky shed. Thanks to owner John Te­store for al­low­ing me the chance to savour a real sur­vivor of the bat­tle­field that was the early ‘eight­ies Su­per­bike scene.

The XS11 as it emerged from the shed. Orig­i­nal Solex carbs have been re­tained for fu­ture re­fur­bish­ment.

Greg Pretty ploughs through the rain to win the Coca Cola 800 with Gary Coleman in Fe­bru­ary 1981.

Tak­ing shape. RIGHT Mak­ing it two wins from as many starts, Pretty pow­ers to vic­tory in the 1981 Arai 500 at Bathurst. LEFT A shot that graph­i­cally il­lus­trates a diminu­tive jockey on a big bike; Pretty on his way to vic­tory in the 1981 Coca Cola 800 at Oran Park. The re­stored XS11 made its pub­lic de­but at the 2018 In­ter­na­tional Fes­ti­val of Speed and drew crowds all week­end.

Un­der­coated frame and wheel com­po­nents.

RIGHT New out­rig­ger bear­ing hous­ing was spe­cially made in 1981.

The editor tries the re­stored XS11 at the 2018 IFoS.

A new set of 35mm Kei­hin CR carbs re­places the orig­i­nal Solex/Miku­nis – for the mo­ment. Heart of the mat­ter; the chain drive in place of the orig­i­nal shaft.

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