TALES FROMTHE SHED

Frank dis­cov­ers a com­plex, slow way to darken the af­ter­noon sun­light…

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Frank dis­cov­ers a com­plex, slow way to darken the af­ter­noon sun­light

The ex­cite­ment of an af­ter­noon in The Shed is al­most be­yond de­scrip­tion. I hardly know where to start this month’s mag­nif­i­cent oc­to­pus, things have been so en­ter­tain­ing. Do I con­tinue with the in­creas­ingly il­lu­mi­nat­ing head­lamp saga, whereby I can al­most find the al­most cor­rect bits and al­most fit them? Or do I dive straight into the gritty nitty and daz­zle you with the sparkling bril­liance of my mag­neto re­fit­ting skills? Not an easy call, I’m sure you’ll agree.

You may recall read­ing Jac­que­line PUB’s ex­cel­lent piece last time about how she re­ceived the CSR’s mag­neto, gave it a se­ri­ous dose of tech­ni­cal look­ing-at and de­cided that only a com­plete chimp would be un­able to pro­duce fine fat sparks from it with al­most no ef­fort at all. I read her words with mi­nor gloom, as you’d surely ex­pect. I have never suc­cess­fully re­built a mag­neto. Or any­thing else, it some­times feels like. I did build a gear­box once. It would se­lect first and third or second and fourth. Life can be a chal­lenge.

That said, fit­ting one of Mr Joe Lu­cas’s K2F mag­ne­tos is hardly dif­fi­cult. Three fas­ten­ings and the tim­ing pin­ion. Did some­one men­tion tim­ing? Ig­ni­tion tim­ing? I’ll get back to that.

First things first. Once this re­mark­able de­vice is back in its right­ful place, I will never ever want to re­move it again. I know this. I also know that you will not want to read about my re­mov­ing it again, so it is im­por­tant to we Noted Ex­perts that we fit the thing prop­erly the first time. Al­though prac­tice al­most cer­tainly makes per­fect, I have no wish to be­come more per­fect in the black art of fit­ting mag­ne­tos. All I want to do with a mag­neto is for­get it’s there, and sim­ply revel in its most ex­cel­lent sparks. Real Ex­perts like Jac­que­line PUB bask in global ad­mi­ra­tion be­cause of their tech­ni­cal ex­per­tise. I am de­lighted about this, and not at all en­vi­ous. A me­chan­i­cal elec­tri­cal ge­nius I have no wish to be. Which is for­tu­nate.

Part of the fit­ting the thing only once in­volves fit­ting it prop­erly, as you may al­ready know. Fail­ure to fit a tech­ni­cal thing like a mag­neto – or worse, a car­bu­ret­tor – sim­ply means that the wretched in­stru­ment of tor­ture will need to be fit­ted more than once. Pos­si­bly very much more than once. I know this. I once fit­ted a car­bu­ret­tor more than a few times be­cause when it was fit­ted the en­gine would not run. It would not run when the carb was not fit­ted ei­ther, but I took no so­lace in that sad fact. Mix­ing up the throt­tle and choke ca­bles is an easy mis­take to make.

Part of my re­lent­less pur­suit of per­fec­tion in­volved search­ing for all the pe­riph­eral – read ‘non tech­ni­cally dif­fi­cult’ – bits which

trans­port the awe­some dis­charge from the mag­neto to the spark plugs, en­sur­ing rid­ing de­light for Proud Owner. Which would be me, in this case. It is easy to ac­quire the ca­bles and stuff, of course. All a chap needs to do is storm off to the near­est event which has a de­cent jumble, seek out the pur­vey­ors of such tackle and buy it. Can you spot the flaw in this?

As I write this, the UK is still in the clammy grip of The Great Lock­down, which means of course that au­to­jum­bles and old bike events are some­what thin on the ground. This has been the case since the glo­ri­ous mag­ne­toid relic of our great Bri­tish elec­tri­cal in­dus­trial her­itage re­turned from PUB’s pala­tial es­tates in the re­mote east of this wide is­land. But never mind. Sev­eral fine em­po­ria have re­mained open ether­i­cally to ser­vice needs such as mine. Hur­rah. I zapped on­line to find the bits I need to con­vey sparks to plugs.

And I found them. I found a wide va­ri­ety of them. And I found that it is still – amaz­ingly – pos­si­ble to ac­quire gen­uine Lu­cas bits in gen­uine Lu­cas boxes. This is as­ton­ish­ing stuff. I should of course not have been even faintly as­ton­ished, be­cause I’d dis­cov­ered the ex­act same thing when seek­ing bits for the great head­lamp re­place­ment ex­er­cise. That had not been an en­tirely de­light­ful process, mostly be­cause too many of the nice new nick­nacks ei­ther didn’t fit or didn’t work, which is ir­ri­tat­ing. And a waste of both time and money.

I am of course the very def­i­ni­tion of an eter­nal op­ti­mist, and or­dered the parts I needed. Some­times I or­dered the same thing more than once. This is be­cause with age comes for­get­ful­ness. I think. I could be wrong. Who knows?

Let’s make up some nice new HT leads. What could sim­pler? Did you know that mo­tor­cy­cle HT leads are 10mm in di­am­e­ter? I’d never given HT lead di­am­e­ter a sin­gle mo­ment’s thought in a half-cen­tury of hap­less two-wheel­ery. HT leads are sim­ply HT leads. All I knew – if in­deed I knew any­thing, which seems un­likely – was that I needed to use old-fash­ioned copper-cored HT lead and not some mys­te­ri­ous mod­ern non­sense which uses no copper at all, but some mag­i­cal black stuff which claims to be car­bon. I know noth­ing about that, of course. c What I now know, how­ever, is that HT leads are avail­able in more than one di­am­e­ter. I now have sev­eral ex­am­ples. 10mm is what we w need. Not 7 or even 8mm. Ten. The strim­mer with which the Bet­ter Third T cheer­ily de­stroys en­tire swathes of hap­less plants uses 7mm HT le ead, formed into a sin­gle uni­fied item with both the pick-up and plug cap. c This knowl­edge, al­though im­pres­sive, is of no use what­so­ever when w equip­ping a K2F Lu­cas for a Match­less mo­tor­cy­cle. But I try to be b help­ful.

Hav­ing fi­nally ac­quired the cor­rect HT lead and a nice smart set of pick-ups, p gas­kets, lit­tle brass split wash­ers and plug caps – all branded Lu­cas L and sup­plied in smart green boxes, I set to, ap­ply­ing the se­cret

skill which is mak­ing up plug leads. Can there be a more sat­is­fy­ing, re­ward­ing en­ter­prise? No need to an­swer that. First…

…I re­fit­ted the mag­neto. This is a good idea, if only be­cause it makes gaug­ing the lead lengths re­quired easy. Tim­ing can wait.

Next, the pick-ups, both com­plete with nice new car­bon brushes (and I have a cou­ple of spare new sets of brushes, be­cause … you know… be­cause). Nice neat job. A job well done, I con­sid­ered. Next, of­fer up the pick-ups to the mag­neto it­self, re­mem­ber­ing to fit the nice new (and pe­cu­liarly pink) gas­kets. Nice tight fit over the process on the pick-up body. Of­fer up the as­sem­bly to the mag­neto body. It re­fuses to seat. This is no use at all. Rain might get in, and Jac­que­line would tell me off. A puz­zle: why don’t they fit?

Be­cause the re­mark­able pink gas­kets are not quite the right shape. File the gas­kets. Now they fit. Why not, I ask again with only a tinge of ex­as­per­a­tion, make the things the right size in the first place? It would cost no more and would en­cour­age me to buy more stuff from the sup­ply­ing com­pany. Mov­ing on…

Mea­sure up the length of lead re­quired to al­low it to reach the spark plug from above, be­tween the rocker­box cov­ers rather than just dan­gling around, as we so of­ten see. Why dan­gle leads all over the place? It’s messy and when it rains you can ex­pe­ri­ence the rare de­light of sparks jump­ing be­tween the lead and your leg. This pro­duces a mys­te­ri­ous mis­fire, as you may know al­ready.

Right. On with the hand­some shiny black plug caps, non-sup­pres­sors, be­cause mod­ern tel­lies don’t gen­er­ate snow when you hooli­gan past on your bikes, so ru­in­ing the evening’s episode of Z-Cars, or what­ever. The caps are nice and shiny. Did I say that? The first one broke as soon as I screwed it onto the lead. The lit­tle brass screw con­nec­tor sim­ply snapped. I tried the other. Same re­sult. Plainly that Charles Atlas course with Dy­namic Ten­sion worked. I am a su­per­hero with su­per­strength. This is good to know but un­help­ful when re­assem­bling an ig­ni­tion sys­tem. I threw away the gen­uine Lu­cas bits. Rub­bish. Gen­uine rub­bish.

Hap­pily, in the top drawer were a pair of less flam­boy­antly branded plug caps. They were mod­est about it, but care­ful ex­am­i­na­tion re­vealed that they were made by NGK, a Japanese com­pany of which you may have heard. Un­like the Lu­cas junk they fit eas­ily and strongly, and even come with lit­tle rub­ber boots to keep out the rain­wa­ter, should I be so un­lucky.

There’s no putting it off any longer, is there? I cast about for ex­cuses – I even mowed the lawn, such was my des­per­a­tion – but no, it re­ally was time to set the ig­ni­tion tim­ing and to close up the tim­ing case. Hang on! The throt­tle cable’s inner is miles too long. I must re­place it at once with an item of the cor­rect length. But the strangely wrong cable claims to be the right cable? O joy! More pro­cras­ti­na­tion op­por­tu­ni­ties! I dug out a pile of new ca­bles left over from decades of time wast­ing but valiant re­builds. One marked as suit­able for a 1971 500 Tri­umph fits the 1965 650 Match­less per­fectly. That didn’t take long. Back to the ig­ni­tion tim­ing.

Why I make a fuss about this I have no idea. It’s ac­tu­ally re­ally easy. I know this. Given that I know this and have in fact timed many many ig­ni­tions, why do I make a fuss? Life is end­lessly puz­zling.

Should you be on a quest for ar­cane in­for­ma­tion, I can re­veal that this is what you need to know: 650cc AMC en­gines need to be timed with the right-side pis­ton at 11/32”, which is 35°, be­fore top dead cen­tre. There you go. You need never to lie awake fret­ting about this again. Set­ting the pis­ton at the cor­rect point is easy too. Most folk I know use a spoke from a wheel to poke into the plug hole to mea­sure the dis­tance. I use a lit­tle tool I picked up at a jumble which is pos­si­bly even less in­ac­cu­rate than an old spoke marked with magic marker.

Whip off the in­let valve cover (easy on AMC’s el­e­gant twins), then turn the en­gine us­ing the kick­start lever un­til the pis­ton is ex­actly at the top of its stroke af­ter the in­let valve has closed. Screw in the lit­tle tool to check that the pis­ton is where it should be. Prom­ise choco­late re­ward to some­one con­ve­niently prox­i­mal

– I pre­fer to ask the Bet­ter Third to do this,

be­cause she is sym­pa­thetic about things like ig­ni­tion tim­ing – and in­struct them to gaze at the lit­tle marks on the lit­tle tool, ex­plain­ing that you are go­ing to per­form Com­plex Boy Stuff and wind the rear wheel back­wards while she looks at the lit­tle tool. She will, at this point, gaze upon you as though you never had any mar­bles, never mind lost them. Smile en­cour­ag­ingly and say, brightly ‘You’ll see the lit­tle thing move down un­til it reaches the lit­tle line I showed you.’ Smile more, and try to look in­tel­li­gent.

Heave on the wheel.

At this point your hope­fully glam­orous as­sis­tant will say some­thing like: ‘OK, it moved. It’s past that mark now. Now what?’ Try not to scream, be­cause you will cer­tainly re­gret that later and at length. It was, re­mem­ber, your ex­pla­na­tion that was at fault. Be cheer­ily help­ful about this. Be­cause even­tu­ally you will, be­tween you, get it right.

At this point, you re­mem­ber that you should have checked that the mag­neto points gap was be­tween 0.010” and 0.012”. This should be checked be­fore the wheel-heav­ing thing, be­cause choco­lates are de­cently costly and funds may be tight. Be brave: we’re nearly there.

The pis­ton is now at the point where the con­tact breaker should be about to sep­a­rate. In olden times, en­thu­si­asts stranded at the road­side in thick fog and pour­ing rain would check for the ex­act points sep­a­ra­tion mo­ment by us­ing a pre­sum­ably sog­gily dis­in­te­grat­ing fag pa­per, but we move in en­light­ened times and the bike’s on a bench and I have an elec­tric me­ter, which is good at this kind of cir­cuit spot­ting thing. Set the lit­tle fi­bre foot-thing on the cam ring thing at the sep­a­ra­tion point and stand back. Time to breathe and to con­tem­plate the many ad­vances made in mo­tor­cy­cle ig­ni­tion sys­tems since your bike was built. Then take a deep breath, be­cause it is now time to con­nect the mag­neto’s drive to the en­gine.

And it is very easy to ro­tate the mag­neto’s ar­ma­ture while tight­en­ing the nut which holds the tim­ing pin­ion onto the ar­matur re’s ta­pered shaft. This com­pletely wastes all that time you spent set­ting the points at the ex­act break point. And did you re­mem­ber to set the man­ual mag­neto at full ad­vance be­fore you set the points? Of course not. Do it now and re­peat what you’ve al­ready done, at least twice. Prac­tice maketh the man. Or some­thing. Your own Bet­ter Third need not be present for this, so it is OK to blas­pheme, at least a lit­tle. Ex­cept on Fri­day, Saturday or Sun­day, de­pend­ing upon your re­li­gious in­cli­na­tion. Maybe all three days, just to be on the safe side. Right then. I’d set it up. I re­fit­ted the tim­ing cover, us­ing no gas­ket be­cause I’ve never seen one fit­ted to an AMC twin tim­ing case, and tight­ened all those lit­tle screws with great care. Only one of them ap­pears to be stripped, which is good go­ing for one of these en­gines, and I stuck that screw in place with a lit­tle dob of thick grease, like you do. Or like I do, in case you do not.

And then, be­ware, for the mo­ment of truth ap­proaches. But be­fore that, a chap should fit the fuel tank prop­erly, not in some half-hearted way us­ing all man­ner of mys­te­ri­ously ran­dom fit­tings. Pause. Ig­nore that bit. I de­cided at that point that I sim­ply wanted to see whether the thing would run – Jac­que­line as­sured me that it would and she is never wrong – so I just rested the fuel tank on the frame, added fuel, made ab­so­lutely sure that the Bet­ter Third wasn’t nearby, so had no inkling that fail­ure and de­spair were about to set in, and I kicked it over a few times.

It started. Well… it fired, once. I tick­led the carb and said gen­er­ous things to no one in par­tic­u­lar. Set the choke

about halfway and kicked with vigour. It started. Prop­erly. Both cylin­ders. My gob was smacked. It al­ways is at the start-up mo­ment, some­how, even though I do in fact know that it should.

My eyes started to wa­ter. Was this a supreme emo­tional mo­ment? No, my eyes were wa­ter­ing be­cause The Shed was fill­ing with acrid smoke. The smoke was blast­ing in huge swirling bil­lows from the CSR’s silly fat si­lencer. This is be­cause well-worn AMC twin oil pumps sump if left stand­ing for a few years. Three things re­sult from this well-known phe­nom­e­non: clouds of smoke, oil re­turns mu­cho rapido to the oil tank, be­cause that oil pump is a good pump, and a huge pool of filthy oil forms on the bench be­cause crank­case pres­sure blows oil from the crank­case through the drive-side main bear­ings, into the pri­mary chain­case and then out of said case through the hole pro­vided to al­low breath­ing and onto the bench. Or floor, de­pend­ing.

As I was con­grat­u­lat­ing my­self in an only slightly im­mod­est and hys­ter­i­cal way, I be­came aware of the pres­ence of the Bet­ter Third, who was ap­pear­ing and dis­ap­pear­ing again through the vast drown­ing clouds of dense smoke. Smoke which, in­ci­den­tally, dis­cour­ages in­sect life from nest­ing in the rafters. AMC thought of ev­ery­thing. But what was she do­ing? She was wav­ing her cell phone around. This is mys­te­ri­ous be­hav­iour, even for a young woman high on the prom­ise of im­mi­nent choco­late over­load, but…

The en­gine stopped. It had in fact run out of fuel. The Bet­ter Third was in hys­ter­ics. ‘ That’s go­ing to crack them up on Face­book!’ she cried, van­ish­ing again. And she was cor­rect. As al­ways…

The old pick-ups. Maybe there’s a clue to the non-run­ning here?

One ex­pertly re­fur­bished mag­neto, ready for re­in­stal­la­tion

The way we were: a ma­g­less Match­less, poised

Tim­ing side in­let valve: how to get your pis­tons in the right place for the sparks

One of the new pick-ups. Ob­serve how the gas­ket is ac­tu­ally too large. The new brush, how­ever, looks en­cour­ag­ing

You’re cor­rect. The lit­tle brass screw should not just shear off like this

Find­ing TDC is easy with one of these, and it has handy lit­tle marks for you to lo­cate the right pis­ton po­si­tion for tim­ing

Where the spark starts for the right-side plug

FW’s NOS (aka, old junk) box comes in handy again

a nice new gas­ket of course

One ofthe more use­ful toolsinThe Shed­tool­boxes

One mag­neto, back in place, com­plete with

Guess what! Some gen­tle ex­haust ex­ha­la­tions may be ap­par­ent…

Tank rest­ing in place, fuel line con­nected. This ma­chine should run

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