YAMAHA C3SC

It is re­assem­bly time and things are go­ing sus­pi­ciously rather well!

Classic Motorcycle Mechanics - - CONTENTS -

Scoop reck­ons it’s on its way!

I’ve now reached the stage in any re­build where, hope­fully at least, the pos­i­tives have be­gun to out­weigh the neg­a­tives. The bike is slowly be­ing re­assem­bled or at least I’m build­ing sub-as­sem­blies ready to re­in­stall. Ev­ery­one has their own se­quence of re­build­ing but mine gen­er­ally com­mences as fol­lows. In­stall the cen­tre­stand with its as­so­ci­ated fit­tings i.e. the spring, the C-shaped cen­tre stand link, and, if ap­pli­ca­ble, the rear brake arm. Over the years I’ve been frit­ter­ing away my life on old bikes it’s be­come ob­vi­ous that if the stand and its gub­bins don’t go on first they’ll be a pig to do later. It’s al­most as if the bike is built around it, not un­like a French car of the 1970s where the en­tire ve­hi­cle is con­structed around the cig­a­rette lighter… if you’ve been there you’ll know ex­actly what I mean! The orig­i­nal cen­tre­stand pin wasn’t in the best of health when I first looked at it and the per­cus­sive per­sua­sion needed to evict it didn’t help. My NOS and re­cy­cled spares yielded sev­eral likely pins but they were all too thin; the CS3C’S pin is unique to the pre-1972 bikes and, of course, is no longer avail­able. The groove that lo­cates the re­tain­ing E-clip didn’t look healthy so it should have been ei­ther a re­place­ment, or re-man­u­fac­ture job but my mate Bob came up with an ef­fec­tive and in­ge­nious re­pair which I think does the job fine. The re­mains of the re­tain­ing shoul­der were machined off, a 6mm hole drilled and tapped then a stain­less steel penny washer machined to suit as a re­tainer; I se­ri­ously doubt it’ll stand out once the bike is back to­gether. Next up was the sus­pen­sion, both ends hav­ing been cos­met­i­cally re­freshed and/or re­built. The fork legs un­for­tu­nately yet pre­dictably bore Stil­son scars (other pipe wrenches are also avail­able) so they went off to A M Philpots for fresh hard chrome. The rear shocks were var­i­ously rusty and cov­ered in rat­tle can sil­ver so they were stripped, re-chromed and re­built. The most labour in­ten­sive part was fet­tling the grey in­ner shrouds that sup­pos­edly pro­tect the damper rod and seal when the bike is rid­den off-road… yeah, right! Hideously scarred and spec­tac­u­larly stained with rust from the springs, a whole af­ter­noon was squan­dered on two plas­tic tubes. Sand pa­per, wet ‘n’ dry, kitchen cleaner and plas­tic head­light pol­ish fi­nally got them back to be­ing rea­son­ably tidy.

The bot­tom yoke re­ceived a full com­ple­ment of con­sum­ables, bear­ing races, balls, top nut and cover cour­tesy of Yam­bits, ready to re­ceive the fork legs. Swingarm back in place with new bushes the shocks were sim­i­larly re­homed, fi­nally giv­ing the bike some sem­blance of or­der. Of course there had to be a curve­ball or it wouldn’t be one of my projects. The rub­ber fork gaiters are sup­ported and cen­tralised at the top by a de­vice called spring re­tainer, up­per or some such moniker. When the bike ar­rived from Canada the en­tire front-end was al­ready off but I re­call a pair of wickedly lethal steel press­ings sit­ting in the gaiters. Of course th­ese had va­por­ised into thin air come re­build time which caused some con­ster­na­tion. How­ever, de­spite the parts book di­a­gram in­di­cat­ing some­thing vaguely sim­i­lar and sharp the im­ages of said items on ebay were to­tally dif­fer­ent and clearly moulded plas­tic discs. On the ba­sis that the lat­ter looked cor­rect, Bob and his lathe were once again press­ganged to knock up some­thing sim­i­lar. Still naively telling my­self that this is not a full restora­tion, the brake hubs re­ceived some at­ten­tion cour­tesy of my dwin­dling stock of old-style (read: ac­tu­ally works) paint strip­per. The orig­i­nal lac­quer on the brake plates was stripped off and the bare al­loy buffed up to an ac­cept­able level but not overly blinged; note to self, don’t wear de­cent clothes next time you get the pol­ish­ing stuff out. De­spite check­ing them be­fore and pro­nounc­ing them okay, I found the wheel bear­ings were now notchy so some new bear­ings were in­stalled. I chose to use the dou­ble shielded type as they are lit­er­ally only pen­nies more than the sin­gle shielded ver­sions but in­fin­itely bet­ter pro­tected. And of course while I was deal­ing with brake plates and wheels it would have been fool­ish in the ex­treme not to have fit­ted new brake shoes. I know I bang on about this far too of­ten but you re­ally shouldn’t be as­sum­ing a set of lin­ings are okay after al­most 50 years. There’s a well-doc­u­mented is­sue whereby, over time, the ad­he­sives used to bond the fric­tion ma­te­rial to the al­loy cast­ing be­gins to fail. At best your brake will sud­denly come on as the liner frac­tures and breaks up. At worst you may find your­self dumped on your ear as one or both wheels locks up. For that rea­son if no other the OEM shoes were dumped in favour of EBC’S finest which fit­ted like dream.

Moving away from the chas­sis I’d no­tice the tacho or speedo had some gravel rash to its case. Fear­ing the worst in terms of in­ter­nal dam­age, I con­nected it to my cord­less drill and via a square drive adapter span the gauge up us­ing the anti-clock­wise set­ting. Amaz­ingly, the nee­dle ro­tated as it should and didn’t flut­ter. The cracked mount­ing pin’s base was sorted with some Supa-fix and the scars filled in with some plas­tic metal. Thank­fully the CS3C runs painted clock cases so there was no need to get th­ese re­plated. Some ju­di­cious mask­ing and a few crafty coats of crackle black had both gauges back al­most like new… re­sult and no stupidly ex­pen­sive out­lay ei­ther! Fit­ting the re­built forks should be a straight­for­ward task but with ex­ter­nal springs you have to push or pull the whole as­sem­bled leg up through the lower yoke to fit the newly painted head­lamp brack­ets. With the forks nipped up at the lower yoke, and var­i­ous col­lars, damper rub­bers, painted parts, top yoke, fork nuts and wash­ers loosely in place ev­ery­thing is then lined up. Gently slack­en­ing the lower yoke pinch bolts sees the fork springs pull the whole assem­bly into place ready to be tweaked and tight­ened later. And I didn’t even man­age to mark the paint! Moving ahead, all of my chrome plat­ing is back and although it’s never cheap it’s great to be able to tick an­other key task off the list. Know­ing how rare guards are for the street scram­bler I’ll be ap­ply­ing some se­ri­ous pro­tec­tion to their un­der­sides by way of an in­sur­ance pol­icy. The front blade bolts to its tubu­lar cra­dle via four U-clips that carry no Yamaha part num­ber util­is­ing no fewer that 14 bolts, 14 spring wash­ers and 14 nuts… now what could pos­si­bly go wrong?

One stand pin!

Kit needed to pol­ish the hubs.

Time to check the clocks!

Strip­ping the hub: lit­er­ally!

Brake shoes in.

New wheel bear­ings.

Re­pair­ing and mask­ing the clocks.

What you need to pol­ish plas­tic.

Shock re­build time.

The Yamaha’s yoke/stem.

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