Re­build­ing to use

There are many rea­sons why a re­build or restora­tion is started, but a house move has to be the odd­est… Project 90 is on the go.

Classic Dirtbike - - Contents - Words and pics: Tim Brit­ton

The time has come, the need is there, the re­al­i­sa­tion that wheel­ing a bike from shed to shed is a whole lot eas­ier than car­ry­ing it in boxes.

In the 16 years or so I’ve been writ­ing about mo­tor­cy­cles, a re­cur­ring theme for restora­tions has been “…took it apart years ago then moved house and it got for­got­ten…” Well, flip that around, as dur­ing a re­cent re­lo­ca­tion, when I had to shift all the bits I’ve ac­cu­mu­lated over 45 years of mo­tor­cy­cling, it was sug­gested that some of the bits might be eas­ier to move if they were in one bit. I can’t fault the sen­ti­ment, as there have been sev­eral attempts to build these bits – all orig­i­nat­ing from var­i­ous 350/500cc Tri­umphs – into a mo­tor­cy­cle and, each time, life has in­ter­vened.

The first at­tempt came dur­ing my ed­i­tor­ship of Clas­sic Bike Guide but a ma­jor in­ci­dent with the 650 Tri­umph in reg­u­lar use di­verted the funds saved for a lit­tle unit project. Then it sur­faced again in Old Bike Mart when a tech feature was needed and now this bike will also feature in our sis­ter pub­li­ca­tion The Clas­sic Mo­tor­cy­cle as a re­build is needed in it too. Per­haps ‘re­build’ is the wrong word, as the bike has never been in one bit and is just a col­lec­tion of parts amassed over a num­ber of years. You know how it goes, bits ar­rive in the shed some­how, bits turn up af­ter other peo­ple have a clear-out and then the tip­ping point comes… that point where the line be­tween ‘col­lec­tion of parts on the shelf’ to ‘po­ten­tial project’ be­comes fuzzy and sud­denly you’re the wrong side of it.

Okay, the plan is to pro­duce a us­able mo­tor­cy­cle from a col­lec­tion of parts while work­ing to a bud­get, the re­sul­tant ma­chine will be road le­gal – all my bikes ei­ther are, or can be – and will be used for as many things as it can be. In the case of CDB the ob­vi­ous route is to make the bike an en­duro / isdt style, which can be scram­bled, hill climbed and en­duro’d, while in TCM the project will have more of a road base be­cause that’s what is ex­pected there.

It isn’t a cop-out to use a Tri­umph as a base and the only rea­son it’s be­ing done is that the bits are avail­able and well, Tri­umph is pretty much the best bike in the world next to Bul­taco… feel free to agree or even dis­agree. The facts that a lot of parts are in­ter-change­able and Tri­umph used barely con­verted road­sters in com­pe­ti­tions makes the project a lot more vi­able when you add in that Tri­umph parts are still eas­ily avail­able, even in 2018, and things look even bet­ter.

Like many of these projects there has to be a plan or it will fal­ter and while it has been a while since bits started ar­riv­ing – 1981 if mem­ory serves me cor­rectly – the plan was for­mu­lated around 1990 with a glance at an Osprey book en­ti­tled Tri­umph Twins and Triples, one of Roy Ba­con’s works. Inside was a pic­ture of an ISDT Tri­umph circa 1961 to be rid­den by the late Roy Pe­plow and based on the unit 500 road­ster. Once I twigged the ma­jor­ity of the parts were from the road range there dawned a fo­cus for the project.

There was a slight side­track, well, sev­eral if I’m hon­est, but the main one came with pic­tures of the Ad­ven­turer-based 1973 ISDT ma­chines, which were very nearly rid­den to vic­tory in that mo­men­tous Amer­i­can-based ISDT. These specials were in­spired by the Tri­umph-en­gined BSA Vic­tors used in the 1966 ISDT and fea­tured in is­sue 45 of CDB. I

fell into the trap of think­ing I’d find a cast-off Vic­tor frame and bung one of the Tri­umph en­gines in it, stick some Be­tor forks in the front, add some comp wheels and away we’d go. As many oth­ers who have at­tempted such a project found, while the frame used on the BSA specials and the Ad­ven­turer was in­spired by the Vic­tor, it isn’t quite the same. The fac­tory used the Vic­tor’s di­men­sions and eased the bot­tom cra­dle so the weight distri­bu­tion would be cor­rect when the en­gine was in place. Not an im­pos­si­ble job to recre­ate, but not an easy one ei­ther.

A bit more re­search showed that while the BSA specials were sup­posed to be pro­duced across the board for the Trophy and Vase teams, a bit of in­ter-fac­tory ri­valry meant what was pro­duced were four of the specials and the pre­vi­ous year’s Tri­umphs re­fur­bished. The Tri­umphs were also fit­ted with the Vic­tor’s forks and yokes, as this isn’t a dif­fi­cult job to do.

So, in or­der to progress the build I’ve set­tled on the 1966 Tri­umph, as used by Johnny Brit­tain and Roy Pe­plow, as the ideal to aim for, but us­ing such parts as I have, ac­cu­mu­lated over a num­ber of years.

What have I got?

The bits I’ve ac­quired have all been be­cause they were avail­able with­out any con­scious ef­fort to get ev­ery­thing from a par­tic­u­lar year. What I’ve got is a frame from 1959, a sub­frame from some other year, a swingarm from 1963… be­cause that was a con­scious pur­chase at the Stafford Show a few years ago and the ven­dor said it was a 1963 part. There’s a slack hand­ful of fork yokes, in­clud­ing a rare com­pe­ti­tion top lug, as fit­ted to Bon­nies and TR6S and the oh so sexy-look­ing TR5A/C for the US mar­ket.

I’ve a bunch of en­gines, some com­plete, some in bits, but all are the dis­trib­u­tor-type, which doesn’t mat­ter re­ally, but it means that they’re the plain bush tim­ing side main bear­ing type. Nor does this mat­ter, as that style of main bear­ing worked well enough for long enough and as long as the oil is changed reg­u­larly, there’s not a ma­jor prob­lem with it. As for wheels I’ve a cou­ple

of op­tions here and a pur­chase of some CanAm wheels a while ago sug­gests they could be fit­ted. I have a Tri­umph QD rear wheel avail­able too, but it’s a tonne in weight and I’ve half a mind to see how light I can go with the bike and with the 3TA quoted as be­ing 345lb, maybe an ounce or two can be shaved off with­out go­ing stupid.

An­other heavy lump is the three-gal­lon ‘sports’ petrol tank, which may or may not be used, but luck­ily for­mer BSA works team mem­ber and SSDT win­ner Alan Lamp­kin was hav­ing a shed clear­ing when I dropped the C15 used by his brother Martin in the Six­ties and had un­earthed an al­loy fuel tank – a bit of a home­made thing and he won­dered if I knew any­one who wanted one…

Also in the build pot are some BSA 250 yokes and sev­eral sets of BSA forks. These will fit in well with the ideal bike im­age as will the six-inch Lu­cas head­lamp I found tucked in a box. The bits still to ac­quire are rel­a­tively eas­ily found, al­loy mud­guards, en­gine plates, seat, han­dle­bars, con­trols and cables won’t present too much of a prob­lem to source.

As­sem­bling the lot

Though lots of parts are in­ter­change­able on Tri­umphs and with the right equip­ment and skill and de­ter­mi­na­tion, al­most any­thing can be fit­ted to al­most any­thing else. We’re not go­ing to lob ev­ery­thing to­gether willy nilly – we’re go­ing to check all the bits and see if what we’ve got is com­pat­i­ble with the idyll – trade off what we don’t need and use the best bits. This will in­volve quite a bit of por­ing over parts man­u­als to iden­tify var­i­ous com­po­nents and al­ready has shown slight dif­fer­ences be­tween the 1959 crankcases and the 1961-type.

The later ones have a bear­ing re­tain­ing plate for the mains bush to stop the bear­ing slid­ing hor­i­zon­tally and ro­tat­ing in the hous­ing, which would cut off the oil feed, thus pro­vid­ing an in­ter­est­ing ex­er­cise en­ti­tled ‘how long can the big ends sur­vive with­out oil?’

Though I’ve shifted the parts I’ve got enough times to know what’s in the boxes, I’ve not thor­oughly in­spected the bits, but a brief look while mov­ing house showed some are T90 – the sports 3TA – and have been pol­ished to im­prove per­for­mance. As I’ve no 3TA pis­tons, T90 ones will have to do. I’ve also got a num­ber of bar­rels for the 350 model, but fi­nan­cial con­straints pre­vented me ac­cept­ing an of­fer of 500cc bar­rels. A shame – thanks for the first re­fusal Owen.

The forks will be as­sem­bled in BSA yokes as they’re stronger than Tri­umph ones for my needs. As with the fac­tory bikes I want BSA forks in place and the stan­chions on BSAS are 35mm, while Tri­umph ones are 32mm, I could bore out the bot­tom Tri­umph yoke or lug but opin­ion from those more ‘en­gi­neery’ than me sug­gest this might weaken them

too much. An op­tion would be to have a light al­loy bot­tom lug made up to Tri­umph di­men­sions and maybe in the full­ness of time this will hap­pen but at the mo­ment £20 for a set of Beezer yokes was jus­ti­fi­able.

Work in progress

There has been a lit­tle work done on this project – the crank was stripped and mea­sured be­fore clean­ing, the bear­ing jour­nals were within tol­er­ance and will only re­quire new shells, the sludge tube and trap plug how­ever… I quote “…undo the end plug and re­move the tube with stout wire…” Yeah… right! Af­ter three weeks in a tub of parts-washer fluid, a thread was cut in the end of it with a tap and a bolt was screwed in un­til it rested on a bunch of wash­ers and with­drew it­self. How on earth this tube had passed oil to the big ends is a mys­tery.

There are a cou­ple of stripped threads to deal with, one on the al­ter­na­tor mount­ing studs will re­quire lin­ing up and maybe some of the other threads might end up metri­cised… Prob­a­bly the first task once the work­shop is sorted will be to lay out the bits and see ex­actly what I have got, even if it means as­sem­bling all the bits into an en­gine as a slightly oily first build. 

Frame and sub-frames pose nicely.

There are a lot of bits, but not all of them need re­plac­ing.

It was in one bit at one time.

A 1961 en­gine is to be used, the later ones have a bush lo­cat­ing plate.

Drill out the cen­tre pop, un­screw the plug and re­move the sludge tube...

Will it all go to­gether? Dunno yet.

John Giles demon­strates tyre- chang­ing for ISDT riders.

Will my project look as neat? No rea­son why not. The unit en­gine is a neat motor.

Three weeks soak­ing in the parts washer...

...and out came the sludge tube.

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