THUN­DER­BIRDS ARE GO

Classic Bike (UK) - - CONTENTS - WORDS GARY PINCHIN. PHO­TOG­RA­PHY GARY MARGERUM

When Tri­umphs are in­volved, you can’t have too much of a good thing. Here’s the proof

Well, they will be when Keith Pottinger has fin­ished with them. He was restor­ing three at once when we vis­ited the workshop of this com­mit­ted Tri­umph re­storer

If restor­ing three 1950s Tri­umph Thun­der­birds at the same time sounds like a lot to take on, think again. Not long be­fore our visit to his workshop, Keith Pottinger had four on the go at once – one he’d fin­ished ear­lier had re­cently been sold to a deal­er­ship in Cheshire. The other three are still work in progress while we’re there, though – and there are many other Tri­umphs, most of which look likely can­di­dates for restora­tion.

Keith is a hard­core Tri­umph en­thu­si­ast who is keep­ing him­self more than busy dur­ing his semi-re­tire­ment by restor­ing the old Bri­tish twins. “I’ve done the four Thun­der­birds over a sixth month pe­riod,” he ex­plains. “It’s the first time I’ve worked on four bikes at the same time, but I had all the bits to hand so it made sense. Do­ing the same job four times, it’s like a pro­duc­tion line – a bit like the Tri­umph fac­tory but with­out the wooden tres­tles!”

On his desk in the cor­ner of the workshop are var­i­ous man­u­als along with his old photo al­bum, next to an orig­i­nal 1968 Tri­umph In­struc­tion Man­ual he’s kept from new. The photo al­bum is full of Tri­umphs and Rick­mans.

“As a kid, I built a rac­ing Ban­tam, then a tri­als Ban­tam. I had Tri­umph Cubs and a 350 Jawa. I wanted a Bon­nie when I was an ap­pren­tice en­gi­neer, but they were £395 new so I built a TRIBSA in­stead. It cost me £35.

“All us ap­pren­tices used to build our own bikes. I bought an iron-head Tri­umph, hack­sawed up a frame and built my TRIBSA in 1968. I used to clean it on Satur­day, then go to race meetings on Sun­day with all my mates. Then I’d spend all week fix­ing what had gone wrong, ready for the fol­low­ing week­end’s trip. We went to a lot of the bike road-race meetings. I fi­nally sold ev­ery­thing off when I moved house back in 1979 – cars as well as bikes.”

Like many bik­ers of that era, Keith never quite shrugged off the bug. He re­stored Austin 7s for a while, but even­tu­ally got back

into two wheels and now runs a sweet, red and sil­ver 1961 TR6. “My TR6 is orig­i­nal and I had a 1961 Bon­nie in sky blue and sil­ver, al­though that wasn’t quite orig­i­nal. They got me back into bikes ten years ago,” he ex­plains. “I built the Bon­nie in my shed, but have since sold it, so I’ve been try­ing to get the TR6 ride­able for when the sun comes out. It’s much nicer to ride than the Bon­nie, which vi­brated so much it made my fin­gers go numb.”

Keith is a bal­lis­tic en­gi­neer – he uses spe­cial equip­ment to test guns and mea­sure the per­for­mance of am­mu­ni­tion. He ran the test ranges at En­field for 12 years un­til 1988, but is now a con­sult­ing en­gi­neer for a bal­lis­tics firm sell­ing equip­ment for com­pa­nies to test mu­ni­tions and body armour.

“We ship to 30 coun­tries,” he says. “I only do three days a week now, though. I was 70 just be­fore Christ­mas – I’m wind­ing down so I can fo­cus more on build­ing bikes!

“Ten years ago, when I set about restor­ing the Bon­nie, I quickly re­alised there were plenty of bits avail­able, so I ended up do­ing an­other, and an­other... and so on. Then I started to pick up other Tri­umph projects and re­alised I could sell the re­stored bikes. There’s not much profit in it, though – it takes three months to build a bike and it’s an ex­pen­sive busi­ness buy­ing all the new spares you need. I need to charge for my labour, but as I’m re­tired there’s no need to chase money.”

So why so many Thun­der­birds, Keith? “I pre­fer the pre-unit Tri­umphs, es­pe­cially the rigids. I like sin­gle carbs and iron heads. Those older mod­els don’t seem to vi­brate as much as the later Tri­umphs do. It seems like the more per­for­mance they added, the more the bikes vi­brated.”

The Tri­umph 6T Thunderbird was launched in 1949, look­ing no dif­fer­ent to the es­tab­lished 500cc Speed Twin, but with en­gine ca­pac­ity in­creased by 150cc to give the im­proved power-to-weight ra­tio de­manded by the Amer­i­can mar­ket. The mo­tor fea­tured a 71mm bore and 82mm stroke to give a ca­pac­ity of 649cc, hop­ping up horse­power by 7bhp to 34bhp at 6300rpm and giv­ing a wider spread of torque. The com­pres­sion ra­tio was 7:1, al­though the Amer­i­can mar­ket bikes could run 8.5:1 com­pres­sion thanks to the bet­ter-qual­ity petrol on that side of the At­lantic.

As a pub­lic­ity stunt to sell the new 650, Tri­umph took three ma­chines off the pro­duc­tion line, then had a team of riders ride them to Montl­héry, south of Paris and cover 500 miles around the banked speed oval at over 90mph be­fore rid­ing them back to Meri­den. The bikes still fea­tured a rigid frame and sprung-hub rear wheel, and had lim­ited mod­i­fi­ca­tions: Dun­lop rac­ing rub­ber, KLG rac­ing spark plugs, 25-tooth front sprock­ets (24 was stan­dard) and foot­pegs re­lo­cated to im­prove rider com­fort.

When it came to the pro­duc­tion road bikes, the Amer­i­cans were ini­tially dis­ap­pointed by the Thunderbird’s per­for­mance, al­though that was over­come with a larger-bore car­bu­ret­tor, in­tro­duced dur­ing the model’s first year on sale. More with­er­ing crit­i­cism came from the choice of the what Cy­cle mag­a­zine called the bike’s ‘slate blue’ liv­ery (called Thun­der Blue in the States, but Poly­chro­matic Blue in the UK) that was used on the frame and cy­cle parts as well as the fuel tank.

The colour was later changed to a lighter metal­lic blue, but US deal­ers kept de­mand­ing black enamel frames which were eas­ier to touch up, which led to Tri­umph of­fer­ing an all-black 6T for the Amer­i­can mar­ket in 1953, prompt­ing the 6T’s ‘Black­bird’ moniker. US deal­ers soon ex­pressed their pref­er­ence for the black ver­sion of the Tri­umph, lead­ing the com­pany to is­sue a dealer bul­letin al­most beg­ging them to take some of the un­wanted metal­lic blue bikes that were left un­sold.

In 1955 Tri­umph in­tro­duced the 6T (SA) swingarm ver­sion to the Amer­i­can range and of­fered it in black or blue, while the 6T (AC) rigid stayed in the cat­a­logue for one more year.

Keith built all four of his T-birds as Us-spec ‘Black­birds’, ex­plain­ing: “I like the look of the Amer­i­can-spec bikes with the

‘IT’S LIKE A PRO­DUC­TION LINE – A BIT LIKE THE TRI­UMPH FAC­TORY!’

black liv­ery and the gold tank badges. There’s a pil­lion pad op­tion and rear pegs, but I don’t fit them be­cause it spoils the ‘bob­ber’ look which sells so well.”

One of Keith’s builds is a 1954 model, com­plete with an SU carb which was first of­fered on the 6T in 1952. Two of them are 1951 mod­els, while the one he’d re­cently fin­ished and sold was a 1950 model. The bikes came to him in dire need of restora­tion: “I got two of them from a con­tact in Der­byshire who brings con­tain­ers full of bikes in from the States. An­other was kept in a barn. When I went to pick it up, I spot­ted an­other Thunderbird frame hang­ing up. The bike in the barn was a chop­per with a weird ex­haust sys­tem that I still have – and springer forks, which I sold. The bike had match­ing frame and en­gine num­bers, so I de­cided to take it back to orig­i­nal. The frame had been cut about with all the ‘un­nec­es­sary’ lugs re­moved, so I had to get the brake pedal hinge cast­ing sup­plied by Ace Clas­sics and welded back in place by Abba Mo­tor­cy­cle Engi­neer­ing in South Wood­ham Fer­rers.”

Keith re­lies heav­ily on Ace Clas­sics in south-east Lon­don for his pre-unit Tri­umph parts. “Not only do they have a huge range of stock, most of Cliff’s parts bolt straight on,” says Keith, adding rue­fully: “a lot of the pat­tern stuff you get nowa­days doesn’t. Cliff’s stuff is more ex­pen­sive, but you know it all fits be­cause he takes stuff off old bikes, gets them copied ex­actly, then bolts the replica part on to make sure it fits. Cliff does all the wiring looms for all the mod­els, so we fit them as stan­dard prac­tice.

“I also use Mark Fran­cis Tri­umph Spares, FD Au­tos who have a lot of old stock, and ebay is a great source for sec­ond­hand parts, as is the Kemp­ton au­to­jum­ble. Things like wheel hubs, brake plates and fork bottoms, you can only get them sec­ond­hand now. It’s the same story for crankcases, heads and rocker boxes.

“I get my speedos re­fur­bished by Rus­sell Smal­ley in Not­ting­ham (chrono­met­rics.co.uk). He’s an ex-smiths’ in­stru­ments en­gi­neer who is now run­ning his own in­stru­ment workshop. Cen­tral Wheels re­built all the wheels on the four Thun­der­birds and painted the black cen­tres and gold lines, too – the eight wheels cost £3500. Nor­mally, the guy next door does all my black paint, while Ace Clas­sics do any colour work.”

Work­ing on pre-unit Tri­umphs is not all plain sail­ing, as Keith at­tests: “Set­ting up the clutches on pre-units is a pain. You build them and leave the cover off. Then run them up and down the road. Then seal up the cover. The tim­ing is with auto ad­vance on the mag­neto ver­sions, so you have to take the cover off to al­ter that. All pre-units are the same.

“And while Ed­ward Turner de­signed the sprung hub be­cause he didn’t want a plunger rear end, it’s an ab­so­lute dis­as­ter of de­sign! When you’ve stripped the thing down to re­store it, it’s so dif­fi­cult to get all the springs back in place when you try to re­assem­ble it.”

Keith then adds the over­rid­ing caveat: “Other than that they are all pretty ba­sic to work on. I do my own en­gine work, though I get my cranks re­built by Thurston Engi­neer­ing in On­gar (thur­sto­nengi­neer­ing.co.uk). I’ve tried re-sleev­ing old carbs, but you are bet­ter off buy­ing new. I still use mag­ne­tos – they’re all re­built and are still six-volt. I use gel bat­ter­ies and it’s a solid-state regulator in­side the old regulator box.

“I can build an en­gine in an af­ter­noon, but then I’ve been do­ing them a while. I’m lucky to have a good friend in Tony Reynolds who does the gear­box re­builds. He’s 83, but is a great help in the workshop. Some­body asked me to do an Ariel, but I had to turn the chap down be­cause I know noth­ing about them. I think it’s

‘APART FROM THE SPRUNG HUB, PRE-UNIT TRI­UMPHS ARE ALL PRETTY BA­SIC TO WORK ON’

best to stick to one make – you get to know all their foibles!”

Those “foibles” in­clude the 1954 bikes hav­ing dif­fer­entlyshaped si­lencers to the ear­lier 6Ts, as well as the shape of the na­celle and fork cov­ers chang­ing slightly for each model. Bolts should be in­te­gral with wash­ers, but there were no wash­ers on any­thing on these 6T Tri­umphs. “I tend to use wash­ers to save the paint. Cliff does sell bolt kits, though.”

Keith still likes to get out on his Tri­umphs and makes sure his builds are in good work­ing or­der by road-test­ing each one. “I find all these Thun­der­birds ride dif­fer­ently. They all vi­brate in a slightly dif­fer­ent way, too. It de­pends on gear­ing – but even then, two iden­ti­cally-geared bikes per­form in dif­fer­ent ways.”

Once he has com­pleted the three re­main­ing Thun­der­birds, Keith is look­ing for­ward to other projects like the Rick­man Metisse he dis­cov­ered that had been stored in a barn for 30 years. It’s got the full CRMC cer­tifi­cate from 1986 and we’re cov­er­ing the restora­tion as part of our Barn Find of the Year com­pe­ti­tion.

Keith’s also promised us first dibs on an­other ex­cit­ing project – a mo­tor­cy­cle which, at first, ap­peared to be yet an­other 6T Thunderbird, but check­ing the frame num­ber re­vealed it to be a gen­uine 1957 Tri­umph T100RR dirt-track rac­ing frame.

Ac­cord­ing to Lind­sey Brooke’s ex­cel­lent book Tri­umph Mo­tor­cy­cles in Amer­ica, Tri­umph of­fered a T100R in 1955 and then a T100RR from 1957 un­til 1958. And it’s ob­vi­ous Keith can’t wait to get started on this project. “It’s cur­rently got a 650 en­gine, but I’m go­ing take that out and fit a 6T iron head... then it’ll need a new frame. But I’ve got a 5T 500cc twin en­gine which I can fit a twin-carb head to and put in to the dirt track frame. The 5T forks are same as the 6T’s, so I’m OK with these but I need a dif­fer­ent tank and wheels. The ’57 mod­els had cylin­dri­cal oil tanks...

“It’s turned out to be an even bet­ter buy than I first thought. We’ll see how well that comes up, but I’ve al­ready started buy­ing a few bits for it. I’ve got a cou­ple of Bon­nies to do, too.”

Sounds like the pro­duc­tion line in Keith’s workshop will be rolling for a good while yet...

‘KEITH MAKES SURE HIS BUILDS ARE IN GOOD WORK­ING OR­DER BY ROAD-TEST­ING EACH ONE’

RIGHT: Keith has re­fined his restora­tion process down to a finely-honed art

BE­LOW: Pis­tons on pa­rade in Keith’s wellap­pointed workshop

He’s not all hard-tail – here’s Keith on the orig­i­nal 1961 TR6 he’s fet­tling to ride

Ev­ery restora­tion has to be­gin some­where – and this is the start­ing grid

The workshop’s lit­tered with mainly Tri­umph-re­lated bits and pics

Keith’s Thun­der­birds are built as Amer­i­can mar­ket-spec Black­birds

You know that SU carb that we men­tioned be­fore? Well, here it is on the ’54 model

LEFT: This 1957 T100RR Keith bought turned out to have a hid­den his­tory ABOVE: The writ­ing’s on the wall, where Keith scrib­bles his to-do lists

Newspapers in English

Newspapers from UK

© PressReader. All rights reserved.