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A few in­ter­est­ing ma­chines this time, in­clud­ing one of Frank’s old mo­tor­cy­cles…

the Guzzi twin needs fuel and re­li­able sparks to run. So those are the first ar­eas to check if your project Guzzi doesn’t! Our in­ten­tion was to con­tinue de­tail­ing and sort­ing the chas­sis, wiring and con­nec­tors, so we made room by strip­ping the en­gine of its ex­hausts (which need to be re­moved in or­der to un­bolt the lower fair­ings), car­bu­ret­tors, the sump and its ex­tra spacer.

A plain bear­ing de­sign, the Guzzi twin mo­tor de­pends greatly on its high pres­sure oil­ing sys­tem. The fil­ter com­ing loose is one thing you’ll wish to avoid, and keep­ing an eye on the top-end oil pres­sure line is a ser­vice pri­or­ity. Sat­is­fied with the con­di­tion of the rub­ber el­bows and the hi-zoot Ago breather they con­nect, we re­moved the al­ter­na­tor cover to ac­cess the hex on the crank­shaft’s nose to ro­tate the en­gine.

Back­ing out the screws and pres­sure line banjo fit­tings, the cylin­der head cov­ers come off, ex­pos­ing the rock­ers and ad­justers. Find­ing top dead cen­tre with a wood dowel on top of the pis­ton in­sures both valves are fully closed, al­low­ing for a check of the tap­pet clear­ances. I de­bated pulling the rock­ers to re-torque the heads, but with lit­tle to no leak­age on the gas­ket I left them alone. The lock screw ad­just­ment is easy but nec­es­sary, as the en­gine will not idle smoothly if valve lash is not prop­erly set.

It’s de­bat­able how many big Guzzi twins still fire their plugs with the orig­i­nal con­tact break­ers, but here’s one which hasn’t swapped to a more mod­ern sys­tem. Yet. The key to very long life is keep­ing a fresh bat­tery in­stalled and lim­it­ing use of the ig­ni­tion switch for start­ing only. Ad­just fully opened on the ig­ni­tion cam and oil the lu­bri­cat­ing felt. Just slightly dirty, the faces looked new af­ter a shot of con­tact cleaner and a quick pol­ish with emery pa­per.

Tak­ing stock, with the chas­sis sorted and the driv­e­line ser­viced it was time to ad­dress the grimy Dell’Orto pumpers and in­stall the bat­tery. It was here that time and the un­savoury re­mains of old fuel had done its worst. The ac­cel­er­a­tor pump but­tons were locked solid and the rest was stained with var­nish. Re­build kits are avail­able for most Dell’Orto sizes, and af­ter a thor­ough soak

in PB Blast pen­e­trat­ing oil we me­thod­i­cally re­placed ev­ery O-ring and gas­ket, in­clud­ing the choke plate. Our cus­tom ca­ble maker took a try or three, and the bike would ben­e­fit from a proper To­maselli ¼-turn in place of the cheesy plas­tic throt­tle. An­other ear­lier up­grade is the Del­rin in­takes, which re­store the solid mount­ing of the carb/fil­ter that was lost with the long-dis­carded fac­tory air­box. Guessti­mat­ing equal slide lift with an al­ways ac­cu­rate fin­ger method, the leads were at­tached to the bat­tery, the K&N pods squeezed into place and the ex­hausts bolted back onto the en­gine.

Like most road-go­ing vin­tage Moto Guzzis, the SP is sharp but not over­done. I re­call clearly how the SP looked when my brother Nick rode it home 37 years ago, and to be hon­est the bike isn’t that dif­fi­cult to keep in good me­chan­i­cal or­der. If the check valves are work­ing then the crank­case and trans­mis­sion breathers are ac­tive, and the best way to keep the oil in­side is to re­place worn crush wash­ers wher­ever you find them. Cos­met­i­cally, de­tails count. You can see the Guzzi’s mis­matched fac­tory paint in the pho­tos, but re­plac­ing mi­nor items like the rub­ber grom­mets that at­tach the side cov­ers and keep­ing the steel bar­rel in­side the rub­ber body­work wash­ers al­lows those parts to seat cor­rectly for a tight fit.

While on the sub­ject, be­hold the rat­tle-can magic adorn­ing the SP’s chem­i­cally-rav­aged frame. In­vest­ing years to per­fect my method; I scrape, sand or wire brush away the dam­aged paint un­til reach­ing an un­af­fected area, then wipe it down with paint thin­ner. This one was down to the bare steel in spots, and af­ter tap­ing and mask­ing I blend mist­ing coats us­ing the same bar­beque heat paint I point at the ex­haust. When ev­ery­thing is even, a clean towel is used to buff the al­most dry sur­face to re­turn the same semi-gloss fin­ish which Guzzi sprayed in Man­dello. Sure, the com­pli­ments are nice and I’ve even been asked to ‘re­store’ oth­ers, but the real bonus is know­ing that the in­evitable scrape to fol­low is no cause for de­spair.

Much has been said about the fail­ings of Ital­ian electrics, but I’d had no ma­jor prob­lems dur­ing the last forty-odd years of Guzzi own­er­ship. So it came as a sur­prise when the SP’s starter re­lay flashed (shorted) on the ini­tial stab of the but­ton, and the starter re­mained silent. Con­firm­ing that volt­age was reach­ing the switch and starter, we by­passed the cir­cuit by jump­ing across the so­le­noid with a screw­driver and… noth­ing. MG Cy­cle once again ex­changed parts for a credit card num­ber, and the re­place­ment so­le­noid fit into the SP’s orig­i­nal Bosch unit per­fectly.

Thus equipped, the SP jumped to life in­stantly, end­ing a long hia­tus. A tank of fuel and a few laps around the gar­den warmed the en­gine enough to syn­chro­nise the car­bu­ret­tors, and the Twin Max carb tool is a pleas­ant sur­prise af­ter years of us­ing mer­cury

tubes. It’s pow­ered by a 9V bat­tery. The rest of the body­work was care­fully cleaned and in­stalled, with nor­mal fussi­ness like ad­just­ing clutch free play and tweak­ing the shifter/ ex­haust in­ter­face be­ing hap­pily car­ried out.

What caused the starter fail­ure? I’m still not com­pletely cer­tain, but Alex did note that of the five Guzzi twins liv­ing in­side our work­shop, the SP was the only one run­ning with­out its fac­tory so­le­noid cover.

It’s now ready for what­ever life on the road may throw at it: our one goal of re­turn­ing this old Moto Guzzi to its former re­li­able self has been met. There sim­ply isn’t room to list ev­ery step we took to safe­guard its depend­abil­ity, but de­tails like in­su­lat­ing con­trol ca­bles at wear spots and fix­ing a hose clamp around the oil fil­ter to keep it from com­ing loose are old school lessons learned from ex­pe­ri­ence.

I sim­ply must tout the ben­e­fits of mix­ing Marvel Mys­tery oil in the fuel. In ad­di­tion to be­ing an ex­cel­lent top-end lu­bri­cant, the Marvel ad­di­tive saved us from many frus­trat­ing tasks, and the in­te­rior of the Guzzi’s petrol tank was vir­tu­ally spot­less. Spe­cialty items like body­work and badges are be­com­ing in­creas­ingly dif­fi­cult to find, and the costs of vin­tage Tonti frame parts have sky­rock­eted in re­cent years. Hap­pily, there’s a world­wide net­work of firms of­fer­ing spares and ad­vice, ex­em­pli­fied by web­sites such as Gre­gory Bender’s ‘This Old Trac­tor’ and other en­thu­si­ast lo­ca­tions over­flow­ing with trou­ble-shoot­ing tech­niques and ad­vice. Un­less your project Guzzi is man­gled or suf­fered some other kind of me­chan­i­cal abuse, the work is fun and even ther­a­peu­tic, re­ward­ing the car­ing owner with thou­sands of care­free, char­ac­ter-packed miles.

Rear drive splines. The new one is on the right…

Above right: Handy piece of kit for those who pre­fer to bal­ance their own carbs: the Twin Max carb bal­ancer

Left: Clean­ing and greas­ing the steer­ing head bear­ings

Re­place­ment cush drive rub­bers are usu­ally a good idea

Above: The en­gine was ba­si­cally fine, and a poke around in­side the rocker boxes found no dis­as­ters

Job done. Time to try it out

It is es­sen­tial that wheel bear­ings and spac­ers are fit­ted in the cor­rect or­der

If you’d ever won­dered what an ‘Agos­tini breather’ looked like, well, this is it!

Above: Moto Guzzi Spada, eclipsed by BMW’s tourist twins, but a very fine ma­chine in its own right Above right: Cos­met­ics sorted, the Guzzi’s ready for a longer life Above far right: Ad­mire the neat – and very pe­riod – in­stru­ment lay­out

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