Rick’s Fixes

Write in/get opin­ion

Classic Bike (UK) - - News -

Holis­tic medicine and the work­shop: an un­likely mix? Well, isn’t the con­cept of treat­ing the body as a whole, rather than con­cen­trat­ing on spe­cific symp­toms, a bit like look­ing into why the big-end keeps go­ing in­stead of just doggedly re­plac­ing bear­ing shells? There’s al­ways a big­ger pic­ture. Take Tony’s Rex Acme; three weeks be­fore the Ban­bury Run, he ran low on oil and it seized. “Where can I get a pis­ton in a hurry?” he asked.

Well, you can’t. I use Tri­umph pis­tons, but they need mod­i­fi­ca­tion and a spe­cial smal­l­end bush. So in­stead I sug­gested that he cleaned up the orig­i­nal pis­ton, freed the rings, got the smeared al­loy off the bore and put it back to­gether.

But Tony’s lo­cal engi­neer reck­oned the pis­ton was scrap, a rebore was needed and he should strip and check the bot­tom end. Hmmm, makes me sound a right cow­boy… But then again, just as few doc­tors will ac­cept al­ter­na­tives to pre­scribed med­i­ca­tion, a re­borer in­evitably ad­vo­cates a rebore. That’s OK un­less parts are scarce, then you have to take a wider view. If Tony re-used the pis­ton, it might rat­tle and smoke more but that’s all – and at least it would be back to­gether for the run.

As for the bot­tom end, with to­tal-loss oil­ing there’s no pump to pick up de­bris and in­ject it into the bear­ings – and if the sup­ply stops, the splash sys­tem will starve the pis­ton, first caus­ing it to seize while there is still just enough oil left for the bear­ings.

Tony brought the bike round and we flushed out the crank­case with petrol; very lit­tle de­bris came out and the bear­ings felt fine. Although Tony had man­aged to clean up the orig­i­nal pis­ton, I ma­chined him up a Tri­umph one any­way.

Thing is, the Rex could eas­ily have been await­ing parts for the rest of the sum­mer; in­stead, after a 12-hour day (and a bit of al­ter­na­tive medicine) it’s back up run­ning and ready for Ban­bury.

‘THE ENGI­NEER SAID THE PIS­TON WAS SCRAP, A REBORE WAS NEEDED’

AC­TIVE SER­VICE

Gor­don Dale has bought a 1962 Tri­umph TRW, the 500cc side-valve twin sup­plied to the armed forces. He asks if there’s any way to trace the mil­i­tary his­tory of the bike. I had a word with my mate Will about this, he used to be into mil­i­tary re-en­act­ment and still has a khaki M20 in the garage. Will said that the Bev­er­ley Mu­seum of Army Trans­port are the first port of call and he also ad­vises Gor­don to join the Mil­i­tary Ve­hi­cle Trust (www. mvt.org.uk) who have quite a bit of ex­per­tise and in­for­ma­tion at their dis­posal. The Vin­tage Mo­tor­cy­cle Club li­brary (01283 540557 vmcc. net) hold fac­tory records for Tri­umph and also have mil­i­tary despatch cards de­tail­ing batch or­ders and ma­chine num­bers, so they may be able to pro­vide in­for­ma­tion on when the bike was man­u­fac­tured and sup­plied. The charge for a record search with the VMCC is a very rea­son­able £10 for non­mem­bers and free to club mem­bers

GET­TING THE NEE­DLE

A bit of feed­back from Mal­colm Ross, who has sorted his Tri­umph Speed Twin car­bu­ret­tor prob­lem (last month’s Fixes). He says: “I think your com­ment about float height and carbs built up from mis­matched parts makes you a psy­chic!”

It would save a lot of time in the work­shop if I was… but no such luck, Mal­colm! Any­way, ap­par­ently when he got the bike, the car­bu­ret­ter had an in­cor­rect, 7° float cham­ber – Amal sup­plied var­i­ous an­gles to suit carbs with a down­draft. A new, ver­ti­cal cham­ber was ob­tained from Burlen Fuel sys­tems and came with one of their ethanol-re­sis­tant plas­tic floats and a new nee­dle. Mal­colm was a bit puz­zled to dis­cover that the new nee­dle had two clip notches in­stead of one, as on the orig­i­nal nee­dle, but by mea­sur­ing up he worked out which one to use.

When I sug­gested that the bike’s ex­ces­sively rich run­ning could be due to in­cor­rect float height, Mal­colm took a closer look and this time no­ticed that along­side the two grooves on the new nee­dle were stamped tiny let­ters ‘C’ and ‘P’. These turn out to rep­re­sent the two ma­te­ri­als used for floats: cop­per and plas­tic. Mea­sur­ing the nee­dle from the cop­per float had led Mal­colm to use the ‘C’ groove. Chang­ing to ‘P’ for the lighter plas­tic float led to a huge im­prove­ment. Thanks for let­ting us know, Mal­colm.

BET­TER BRAKE

Jethro Bell writes in from Roys­ton, Herts, to ask if he can fit a twin­lead­ing-shoe front brake to his 1955 Tri­umph T110. As he says: “I don’t ex­pect it to be like my Fire­blade but the stan­dard brake is very poor!”

Tri­umphs of this pe­riod had a

half-width hub with a big al­loy brake plate fit­ted with an air scoop. This brake plate has an an­chor which ex­tends up­ward and is se­cured to the fork with a heavy P-clip. The eas­i­est TLS brake to re­place it with is prob­a­bly a 1968-70 Tri­umph/bsa type, but this is an­chored with a peg on the fork lower and also has spin­dle clamps, rather than the push-through axle of the T110. I think the so­lu­tion would be to change the forks (or at least the fork bot­toms) for the 1957-on type; these are clamp-fit­ting and have a lo­cat­ing peg for the brake plate. You’d need to make sure the peg po­si­tion is the cor­rect height – they dif­fer for 7in and 8in brakes – and that the axle is the cor­rect length to suit the fork width (again, there are two, but these hubs will take ei­ther­length spin­dle. Un­for­tu­nately it’s likely to be a costly busi­ness.

A cheaper al­ter­na­tive might be to con­tact Ian Camp­bell at Clas­sic Brake Ser­vices in the Peak District (07811 356619). Ian of­ten finds car­grade lin­ings have been fit­ted to mo­tor­cy­cle shoes and they are too hard. It’s also pos­si­ble the con­tact area is poor due to drum wear or pre­vi­ous skim­ming; he can ma­chine lin­ings from the cor­rect ma­te­rial to suit the drum, which can make a dra­matic dif­fer­ence. Ob­vi­ously mod­ern brakes are much more ef­fec­tive, but if they are com­pletely hope­less it’s more likely to be an ac­tual fault than just poor de­sign.

Is this freed-off, pre­vi­ously-seized pis­ton fit only for the bin? Maybe not, reck­ons Rick

With a bit of in­tel­li­gence, TRW’S mil­i­tary his­tory might be trace­able

Al­ter­na­tive grooves on new nee­dles can lead to er­rors

Peg on the fork leg an­chors Tri­umph TLS brakes

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