The Potts McIn­tyre story

The be­gin­nings of a won­der­ful re­la­tion­ship: The early years of Bob Mcin­tyre with Joe Potts

Classic Racer - - PEOPLE - Words by: York­shire Fer­ret

As de­tailed in many sources else­where, Bob Mcin­tyre, from Glas­gow, started a very suc­cess­ful rac­ing ca­reer in 1951 on a friend’s 350cc BSA road bike. Af­ter rid­ing it to his first meet­ing, he went on to win three races and crashed out in the fourth. Bob’s nat­u­ral tal­ent was eas­ily ap­par­ent and there­fore it was no sur­prise that he soon found him­self spon­sored by Cooper Broth­ers, of Troon. Suc­cess with the Cooper Broth­ers’ bikes fol­lowed, the high­lights prob­a­bly be­ing Bob’s vic­tory in the Ju­nior and sec­ond place in the Se­nior Manx Grand Prix on the same AJS 7R. Joe Potts, from Bell­shill, Glas­gow, had a rep­u­ta­tion as a suc­cess­ful racer and en­gi­neer. In the early 1930s he won many sand and grasstrack races on Sun­beam mo­tor­cy­cles. By 1934 his fam­ily en­cour­aged him to stop rac­ing and con­cen­trate on his busi­ness com­mit­ments, which in­cluded car and mo­tor­cy­cle sales, a 24-hour garage, en­gi­neer­ing work and even fu­neral di­rect­ing! How­ever, in 1949 Joe took up car rac­ing in a F3 Cooper, which re­sulted in fur­ther vic­to­ries and course records at the likes of Bo’ness and the Rest and Be Thank­ful. Joe’s car deal­er­ship, en­gi­neer­ing busi­ness and per­sonal in­ter­est in rac­ing cars, led him to build nu­mer­ous rac­ing cars, in­clud­ing his own JPS and the highly suc­cess­ful H3 Hop­per Spe­cial. Through this spe­cialised en­gi­neer­ing work Joe ac­quired the rep­u­ta­tion of be­ing Scot­land’s ‘high priest of tune’. He was, how­ever, a shy and slightly ner­vous per­son who avoided the lime­light at ev­ery op­por­tu­nity and it is due to this trait that he never re­ceived the recog­ni­tion he de­served. Joe worked on the cylin­der heads and port­ing for both the Ecurie Ecosse and Le­mans win­ning As­ton Martins, but was never hap­pier than when in the work­shop with his sleeves rolled up and wear­ing a brown smock. Al­ways a mo­tor­cy­clist at heart, in the early 1950s Joe de­vel­oped a 500cc long-stroke Manx Nor­ton on which he would

en­ter nu­mer­ous rid­ers. Joe made his own crank­shaft assem­bly for the ma­chine at Bell­shill. The crank was ma­chined from two pieces of NRM3 steel and heat treated to 60 tons ten­sile strength. The crank­shaft had the main shafts formed in­te­grally with their re­spec­tive fly­wheels and crankpin formed on the left-hand fly­wheel. The two-piece crank was de­signed to be stiffer than the stan­dard Nor­ton item. Joe also made his own con­nect­ing rod for the bike. He had been mak­ing con­nect­ing rods for some time, due to the high com­pres­sion ra­tios and hence the high load­ings from en­gines used in JP and Cooper cars that would use methanol fuel. The con­nect­ing rods Joe made were ma­chined from a solid bil­let of Clyde Al­loy NRM3 steel. Joe’s con­nect­ing rods were shorter than stan­dard items, in or­der to in­crease stiff­ness and for pis­ton ac­cel­er­a­tion rea­sons. The big-end bear­ing for Joe’s en­gine was sup­plied by Al­pha Bear­ings, of Dud­ley. The in­ner race was pressed onto the crankpin and the outer race pressed into the big-end eye of the con­nect­ing rod. Joe also de­signed the crank assem­bly to run in two tim­ing side main bear­ings, in­stead of the orig­i­nal sin­gle jour­nal (stan­dard Manx Nor­tons went to a dou­ble row tim­ing side bear­ing much later in 1956). These main bear­ings were housed in a flanged sleeve screwed into the crank­case, in or­der to pre­vent the outer races from turn­ing. Joe also mod­i­fied the cylin­der head ports to his own spec­i­fi­ca­tion and ob­tained un­ma­chined pis­ton forg­ings to the pat­tern he re­quired. He ma­chined the pis­tons in or­der to pro­duce a squish com­bus­tion cham­ber. He also man­u­fac­tured camshafts for the ma­chine, which re­sulted in both higher rates of valve ac­cel­er­a­tion and peak lift. All this de­vel­op­ment work ben­e­fit­ted from Joe’s first-class fa­cil­i­ties, which in­cluded a Heenan and Froude DXP3 dy­namome­ter. Joe was not a one-man-band and he had a very skilled team of en­gi­neers work­ing

with him. Key per­son­nel in­cluded Adam Smith (fore­man), Joe Wool­lams (en­gi­neer), Alex Crum­mie (fab­ri­ca­tor), Hughie Blair (gas welder), Dick Jones (draughts­man) and David Cooper (ap­pren­tice). The en­gi­neer­ing shop was sec­ond to none, equipped with the very best ma­chines that were avail­able at the time and em­ployed up­wards of 20 full-time staff mem­bers. It is no co­in­ci­dence that when Den­nis Poore’s ex-scud­e­ria Fer­rari Alfa 8C-35 broke a gear­box out­put shaft at the Bo’ness hill climb, Joe and his team were the only ones trusted and ca­pa­ble of ef­fect­ing a re­pair. Rid­ers who had had the chance to ride Joe’s Manx in­cluded George Brown (of Nero fame), Alex ‘Eck’ Phillips and Vic Wil­loughby. Joe’s long-stroke Nor­ton was quick and it was enough to guide George Brown into an ex­cel­lent sev­enth po­si­tion in the 1952 Se­nior TT. Vic’s elo­quent words writ­ten about the 1953 TT are per­haps the best il­lus­tra­tion of the speed of the Potts Manx and the rep­u­ta­tion Joe had built up: “But it was Brown (George) who first gave me a clue as to the sort of per­for­mance Potts squeezes out of his en­gines. George and I were com­par­ing notes in the pad­dock one morn­ing in June 1953 af­ter prac­tis­ing our Se­nior mounts, which were both long-stroke Manx Nor­tons. On stan­dard IOM gear­ing of 4.23:1 (23 tooth en­gine sprocket, 44 tooth rear-wheel sprocket), I was get­ting nearly 6200rpm in top gear (113mph) and was won­der­ing whether I could pull a half-tooth higher suc­cess­fully. George had no such wor­ries. He as­sured me he was geared up no less than 1½ teeth above stan­dard (25-tooth en­gine sprocket, 45-tooth rear-wheel sprocket) and was reach­ing 6500rpm on the level on his re­sul­tant top gear of 3.98:1 (125mph). Brown es­ti­mated his speed at the foot of Bray Hill at more than 130mph and told me that he had the legs of fac­tory Nor­tons dur­ing prac­tis­ing. But for my high re­gard for Brown’s ve­rac­ity I should have been scep­ti­cal of his claims.” To­wards the end of the 1953 sea­son both Joe’s tun­ing rep­u­ta­tion and Bob’s rid­ing rep­u­ta­tion were ex­tremely high. In the lat­ter’s case he had agreed to be­come a works rider for the AJS team for 1954. Char­lie Bruce, the mul­ti­ple Scot­tish 250cc cham­pion and great friend of Joe, had ap­proached Bob to see if he wanted to have a one-off ride on Joe’s long-stroke Manx at the big Char­ter­hall meet­ing to­wards the end of Septem­ber. Bob agreed and trav­elled up from Scar­bor­ough, where on the pre­vi­ous day he had been rid­ing Sam Cooper’s bikes. The com­pe­ti­tion at Char­ter­hall was stiff with the cream of the Scot­tish stars, but also present was the ex­per­i­men­tal short-stroke works Manx Nor­ton that had just won the Manx GP and was to be rid­den by Den­nis Parkin­son. Bob did not need to worry. He won the 500cc event eas­ily on the Potts Manx. This one-off ride left a long-last­ing im­pres­sion on the young Scot as to the speed of a Potts Manx.

Bob spent 1954 as a works AJS rider. It was not a suc­cess­ful or happy time, as he found AMC dis­or­gan­ised and the ma­chines un­com­pet­i­tive. The sea­son left him pin­ing for more com­pet­i­tive ma­chines and a re­turn to Glas­gow. Bob’s mem­o­ries of the speed of the Potts Manx dur­ing his one-off ride en­sured that it was on Joe’s door that he came knock­ing. It was agreed that Bob would ride Joe’s Manx ma­chines and also help run his mo­tor­cy­cle deal­er­ship. This was the start of a very spe­cial re­la­tion­ship. For the start of the 1955 sea­son Joe and Bob had the 1954 short-stroke 350cc and 500cc ma­chines that had been used the pre­vi­ous year. The 350cc Manx had been used at the 1954 Manx GP in un­mod­i­fied trim and it had a top speed of 107mph, a fig­ure that would be raised sig­nif­i­cantly from the de­vel­op­ment car­ried out at Bell­shill. A sim­ple mod­i­fi­ca­tion on the Potts Manx ma­chines was the adop­tion of SU float cham­bers in or­der to bet­ter con­trol the fuel level. Bob Mac (the short­ened name used dur­ing his Potts pe­riod) had a Bed­ford van for trans­port to race meet­ings and if he wanted to con­tinue rac­ing, he would have to win. Rac­ing in Europe was out of the ques­tion due to the large trav­el­ling ex­penses in­curred. It soon be­came ap­par­ent that Bob was achiev­ing enough suc­cess in rac­ing for Joe to close the mo­tor­cy­cle side of his deal­er­ship and con­cen­trate on the more lu­cra­tive car side. This left Bob to con­cen­trate on rac­ing. Bob’s 1955 sea­son started at Brough, and what a start it was. On the 500cc Potts ma­chine Bob man­aged to win the Brough 25 ahead of John Sur­tees on a works Manx Nor­ton. Suc­cess con­tin­ued with good plac­ings at Snet­ter­ton and vic­tory at Oul­ton Park (beat­ing works ma­chines again). At Snet­ter­ton, the 350cc Potts ma­chine re­tired with bevel gear prob­lems. Joe, how­ever, came up with a so­lu­tion for this by mod­i­fy­ing the tim­ing side main bear­ing. The 350cc Potts Manx still was not ready for the Sil­ver­stone Satur­day meet­ing. In­stead, Bob de­cided to bor­row Char­lie Bruce’s Ve­lo­cette MOV spe­cial for the 250cc race. Sadly, the MOV was not go­ing at all well and he only man­aged to com­pete in the shorter 250cc race, fin­ish­ing a lowly 16th. This was Bob’s first and only race on a Ve­lo­cette. On the Se­nior Potts Manx things im­proved con­sid­er­ably, with Bob com­ing home a good third be­hind Ge­off Duke and John Sur­tees (works Gil­era and Nor­ton re­spec­tively). Bob was back in win­ning ac­tion at the end of April meet­ing at Ain­tree, with vic­tory on his Se­nior Potts ma­chine in both the 1000cc and Hand­i­cap races. Back at last on the Ju­nior Potts ma­chine, Bob fin­ished an ex­cel­lent sec­ond be­hind Ce­cil Sand­ford on a Moto Guzzi. Fur­ther wins and good plac­ings con­tin­ued for Bob on the run up to the TT at venues such as the newly length­ened Oul­ton Park, Er­rol, Aber­dare Park and Brands Hatch. The Potts team had been busy pre­par­ing for the TT. Bob’s Ju­nior ma­chine would be fit­ted with a home-built alu­minium ‘dust­bin’ fair­ing. The fair­ing was fab­ri­cated by Hughie Blair at Joe’s work­shop in North Road. To sup­port the fair­ing, a sub-frame was arc-welded out of small sec­tion rec­tan­gu­lar steel tub­ing and this was at­tached to the ma­chine by quick-re­lease air­craft fas­ten­ers. To try to tackle the prob­lem of the front brake over­heat­ing, the bike was fit­ted with a flex­i­ble rub­ber hose that took ‘fresh’ air from an ex­ter­nal scoop to the brake plate. In or­der to try and pre­vent the footrests from ground­ing, Mcin­tyre raised the front forks by half an inch by putting a packer above each fork spring and raised the rear by one inch by mak­ing a new sub-frame and re­plac­ing the shock ab­sorbers. This re­sulted in an in­crease in over­all rear wheel move­ment of 3½in. Bob’s plan for the 350cc bike was that with the new fair­ing fit­ted, it would pull 125mph at 7800rpm down the Sulby straight. The se­nior mount was not fit­ted with the full ‘dust­bin’ fair­ing, as this caused han­dling prob­lems at higher speeds. The 500cc was a very new bike and classed as a spare and as such the Potts team had lit­tle chance to de­velop it. The rea­son why the Potts team could not get the quick 500cc en­gine ready in time was be­cause the cylin­der head cast­ing was found to be por­ous. For this rea­son the most hope was with the Ju­nior mount. Bob was also us­ing the lat­est ex­per­i­men­tal Dun­lop non-di­rec­tional rear tyres on his ma­chines. Bob was tak­ing the TT se­ri­ously and in the first prac­tice ses­sion for the Se­nior, he was sec­ond fastest be­hind Ge­off Duke on his Gil­era, but ahead of the works Guzzi and Nor­ton rid­ers. Bob had been the fastest pri­va­teer for both the 500cc and 350cc classes in prac­tice. The Ju­nior event at the TT was to be the first race to re­ally ce­ment Bob and Joe’s rep­u­ta­tion as be­ing the top pri­va­teer rider and tuner team in the world. Bob’s main op­po­si­tion in the Ju­nior race came from the dom­i­nant works Guzzis (Bill Lo­mas, Ken Ka­vanagh, Duilio Agostini and Ce­cil Sand­ford (Tay­lor tuned Guzzi)) and also from the works Nor­tons and AJSS. As the Ju­nior race started no one was ex­pect­ing Bob to chal­lenge the works teams, but at the end of the first lap he was lead­ing with the same lap time as John Sur­tees on the works Nor­ton. Even bet­ter was to come at the end of the sec­ond lap, as Bob had pulled into an out­right lead on the Potts Manx. He con­tin­ued to lead the race un­til the fifth lap. One com­men­ta­tor de­scribed his rid­ing by say­ing: “Through Union Mills and Glen He­len his torso was welded to the tank top. Up Snae­fell climb he was bril­liance per­son­i­fied”. Af­ter the fifth lap Bob had to stop to re­fuel, which cost him the lead, as Bill Lo­mas went through into first on his non-stop run. At the end of the sev­enth lap Bob fin­ished an amaz­ing sec­ond be­hind Bill Lo­mas, but ahead of Ce­cil Sand­ford and John Sur­tees. The top speed of Bob’s 350 Potts Manx down the Sulby straight had been 123mph at 7600rpm, which was very close to the team’s ex­pected value and re­mark­able con­sid­er­ing that when Potts first got the bike, its top speed was 107mph at The Is­land. It was noted in The Mo­tor Cy­cle that even with­out stream­lin­ing it was es­ti­mated that the Potts 350cc was as fast as the works Nor­tons and Joe was de­scribed as be­ing “with­out doubt one of the fore­most tuners of the day”. with stream­lin­ing, the Potts 350cc Manx was found to be 7mph faster than John Sur­tees’ works bike. Bob’s sec­ond place fin­ish is even more in­cred­i­ble, con­sid­er­ing that from half race dif­fer­ence the Potts Manx was over­heat­ing badly. The first prob­lem was that as the en­gine got hot, this lead to a dis­torted ex­haust valve seat that, in turn, lead to a loss of com­pres­sion. The front fork damp­ing was

also fad­ing badly, as was the front brake. Char­lie Bruce said that at the end of the race Bob’s bike had no front brake left! Joe and Bob also won The Mo­tor Cy­cle Cup, which was awarded to the en­trant whose rider im­proved by the great­est mar­gin upon the av­er­age race time for the ffirst 20 rid­ers, in either the 250cc, Ju­nior or Se­nior classes. At the prize­giv­ing Bob thanked Joe for the ma­chine and “the bits of tin to go round it”. The Mo­tor Cy­cle com­mented about the re­sult: “Many years have passed since a lone pri­vate-owner se­ri­ously chal­lenged three pow­er­ful fac­tory teams and emerged from the bat­tle with so much glory.” In the Se­nior TT on the less mod­i­fied 500cc Potts Manx Bob came home in fifth po­si­tion at an av­er­age speed of 93.83mph. He was once again the first non-works rider to fin­ish the race. Bob was also part of the BMCRC with Ge­off Duke, Ce­cil Sand­ford and John Sur­tees’ team, who won the club team award at the TT

for the Se­nior and Ju­nior races. Since Bob and Joe had won The Mo­tor Cy­cle Cup with their Ju­nior per­for­mance, Joe would get a free entry for the Manx GP. Joe also got an­other free entry due to Bob’s Se­nior per­for­mance. These en­tries would be used in 1956 with great suc­cess. The TT had shown the prob­lem of dis­torted valve seats on the 350cc Potts Manx. Joe, be­ing the sort of per­son who liked to find a good so­lu­tion, started test­ing new valve seat ma­te­rial. Even­tu­ally he set­tled on Hidu­ral 5, which cured the prob­lem. Fol­low­ing the TT, the Potts team were back to short cir­cuit rac­ing. Im­pres­sive wins in both the Ju­nior and Se­nior classes were recorded at Aber­dare Park and Er­rol in June. At the start of July, the Kirk­caldy and District Mo­tor­cy­cle Club ran the Scot­tish speed cham­pi­onships at Bev­eridge Park. Bob and the Potts ma­chines won both Ju­nior and Se­nior races and set new lap records dur­ing the process. Such was his dom­i­nance that in The Mo­tor Cy­cle the fol­low­ing was said about Bob’s rid­ing: “Per­haps the most out­stand­ing fea­ture of the Scot­tish Road Races was the ef­fort­less man­ner in which R Mcin­tyre (Nor­tons) demon­strated his com­plete mas­tery of the art of short-cir­cuit rac­ing.” At the end of July Bob and the Potts team took an ex­cel­lent triple vic­tory at Oul­ton Park (350cc, 500cc and Les Graham Tro­phy Hand­i­cap). The Thrux­ton In­ter­na­tional and Bri­tish Cham­pi­onship meet­ing fol­lowed im­me­di­ately, where the op­po­si­tion would in­clude full works back­ing by the Moto Guzzi, AJS and Nor­ton teams. Bob fin­ished fourth in the Ju­nior and fifth in the Se­nior fi­nal, with Bill Lo­mas, Dickie Dale (Works Guzzis) and John Sur­tees (works Nor­ton) in the top three of these races. Mo­tor Cy­cling mag­a­zine com­mented on Bob by say­ing: “How that Scot­tish lad shakes the fac­tory boys!” In mid-au­gust came the Ul­ster GP, where both Bob’s Ju­nior and Se­nior ma­chines would be fit­ted with ‘dust­bin fair­ings’. The Potts team would once again be tak­ing on all the works teams. Bob was the first pri­va­teer home in both the Ju­nior and Se­nior classes by tak­ing fifth and fourth in each class re­spec­tively. Back in Scot­land, Bob raced at Er­rol, where he com­fort­ably won the un­lim­ited event from Jimmy Davie and Sandy Bowie, but in a thrilling 350cc race he could only fin­ish sec­ond be­hind Alas­tair King, who won on an AJS 7R at 69.20mph. Bob was in Alas­tair’s slip­stream for the en­tire 10-lap race and only man­aged to take the lead for a short time on the ninth lap. It was Bob’s first de­feat in Scot­land since 1952, but it was a de­served win by Alas­tair, who was rid­ing fan­tas­ti­cally. For the 1955 Manx GP, the Potts ma­chines would be en­trusted to Jimmy Buchan, of Perth. This was to be Jimmy’s first ride in the Manx, how­ever he had ex­pe­ri­ence of the TT from the Ju­nior Club­man’s TT in 1954 and 1955. The ma­chines he was to be rid­ing were the ones that Bob had been us­ing through­out the sea­son. On the first day’s prac­tice (Mon­day, Au­gust 29) Jimmy was im­me­di­ately top­ping the timesheets in the Se­nior class at 86.65mph. In Thurs­day prac­tice Jimmy had a bit of bother. He in­tended to do two laps on each of his bikes, but this did not hap­pen. Jimmy went out on the Se­nior ma­chine first, but the gear­box top fix­ing nut came loose at Ram­sey on his sec­ond lap. Jimmy had to tour into the pits and could not make it back in time to take the Ju­nior bike out. In Fri­day morn­ing prac­tice all went well and Jimmy lapped the fastest on his Se­nior bike in the wet con­di­tions. On Satur­day, he went round third-quick­est on the 350 Potts Manx and then in fi­nal prac­tice on Mon­day, un­der wet con­di­tions, he was third and sixth in the Ju­nior and Se­nior classes re­spec­tively. In the ac­tual races Jimmy fin­ished fourth in the Ju­nior and sec­ond in the Se­nior. Fol­low­ing the Manx GP, the Potts ma­chines were back with Bob. At Snet­ter­ton in Septem­ber the main op­po­si­tion came from John Sur­tees. The hon­ours were shared, with Bob win­ning the 350cc class, but fin­ish­ing in sec­ond place be­hind Sur­tees in the 500cc. A third place fin­ish in the 350cc class at the Scar­bor­ough In­ter­na­tional be­hind the works Nor­tons of Sur­tees and Har­tle fol­lowed. To­wards the end of Septem­ber Bob saw some dis­ap­point­ing re­sults at Ain­tree; sixth in the 350cc, fifth in the 500cc and fifth in the solo hand­i­cap. The fol­low­ing day at Brough, he fin­ished sec­ond to Sur­tees in the 350cc class, but had to re­tire from the 500cc event. At the In­ter­na­tional Hutchin­son 100 meet­ing at Sil­ver­stone, Bob was back on form against an im­pres­sive field of works bikes in­clud­ing Ge­off Duke (Gil­era) and the fac­tory Nor­tons of John Har­tle, Jack Brett and John Sur­tees. Bob fin­ished sec­ond in both his 350cc and 500cc heats to John Sur­tees. In the 350cc fi­nal, he was in­volved in a giant bat­tle for sec­ond place with Har­tle, Brett, Ce­cil Cand­ford (Moto Guzzi), J Clark and Bob Brown (AJS). Bob’s dogged­ness pre­vailed and he was able to pull away from the bunch to fin­ish sec­ond be­hind Sur­tees. In the 500cc fi­nal, Bob fin­ished fourth be­hind Sur­tees, Duke and Har­tle. The fol­low­ing day at Brands Hatch he fin­ished sec­ond on the Potts 350 Manx be­hind Sur­tees. Bob did not have his 500 Potts Manx for the 1000cc in­vi­ta­tion race, so he rode a BSA to a very good third be­hind Sur­tees and Alan Trow (both on Nor­tons). As the 1955 rac­ing sea­son ended it was ap­par­ent that it had been a won­der­ful suc­cess for both Bob and Joe. The suc­cess was prob­a­bly most high­lighted by Bob’s me­te­oric ride in the Ju­nior TT. It was there­fore no sur­prise when the fac­tory rac­ing teams came knock­ing on Bob’s door. Ap­proaches were made by both Moto Guzzi and Gil­era. The con­ti­nen­tal circus, star­dom and world cham­pi­onships beck­oned for him – or so it seemed...

Be­low: Joe Potts with George Brown and Wee Jimmy Whyte among oth­ers with a 500cc F3 Cooper.

Be­low: Bob at In­ter­sec­tion cor­ner win­ning the 350cc class at Er­rol.

Right: Alex ‘Eck’ Phillips on the Potts 500cc at the Manx GP.

Pic­tures from: Mor­tons Me­dia Ar­chive

Right: Joe Potts and Char­lie Bruce with the long-stroke 500cc at Bev­eridge Park. Left: Bob Mcin­tyre on the 500cc Potts ma­chine round­ing Wood­cote at the 1955 Hutchin­son 100 meet­ing at Sil­ver­stone.

Be­low: Bob and the Ju­nior Potts ma­chine giv­ing the works teams the scare of their life at the 1955 TT.

Above: Bob Mcin­tyre at his hap­pi­est in the Potts ’din room’.

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