Tabla de contenidos para Issue 40 en Retrobike

ENGINE Air-cooled four-stroke inline six; chain-driven DOHC, four valves per cylinder; 64.5 x 53.4mm for 1047cc: 9.3:1 comp; wet sump; 6 x Keihin CR flat-slides; Dyna 2000 ignition; custom Tranzac exhausts; multi-row chain primary to wet clutch and five-speed gearbox; chain final drive; rebuilt by Nicom, tuned by Steph; 105hp at 9000rpm (stock) CHASSIS Steel tube frame with engine as stressed member, braced and modified by Nicom; 43mm Bimota forks and triple trees, 2 x Brembo 300mm rotors with four-spot calipers on laced 17 x 3in alloy rim; 900SS twin-shock swingarm with small Brembo disc on laced 17 x 5in alloy rim; Pirelli tyres BODYWORK Tank, seat and mudguard by Nicom; 900SS fairing and headlight; paint and graphics by Mark Haywood; Speedhut tacho/speedo SPECIAL THANKS John Boyd, Nic Comolly, Mark…

THE first Cucciolo clip-on bicycle engine differed from similar products from other manufacturers in that it was an OHV four-stroke in a sea of smoky, plug-fouling pre-mix two-strokes, but was not especially reliable and was prone to overheating. Initially built from 1946 under licence to Turin tuning workshop SIATA, Ducati chief engineer Giovanni Fiorio comprehensively redesigned the engine in 1948 with a modified cylinder head and separate cylinder (both made from aluminium) and new crankcases, amongst other things, with power up from 1.25hp at 5200rpm to as much as 2hp in the ‘Sport’ version. Known as the Cuccioli T2, it is regarded by many as Ducati’s first engine. A novel feature of all early Cucciolos is overhead valves operated not by pushrods but pullrods. Instead of a pushrod operating directly…

THE 1920s was a boom time for motorcycles on both sides of the Atlantic. In the US, Harley-Davidson and Indian battled for supremacy in a crowded field, ditto Norton and Triumph in the UK. All four had benefited from large orders from the armed forces during the Great War of 1914 to 1918, which provided the platform for popular consumer models during the economic renaissance of the 1920s. Triumph’s early big seller was the flat-tank Model H, like the Norton 16H a 500cc side-valve single built more for reliability than performance. Technical innovations soon followed, like the adoption of chain final drive (in place of leather belts) on the 550cc Triumph Model SD in 1920, and the souped-up 500cc Model R the year after, featuring four overhead valves. The exuberant,…

ENGINE Air-cooled four-stroke 45-degree V-twin; OHV, two per cylinder; 3.25 x 3.625in for 61 cubic inches (986cc); 7:1 comp; dry sump; chain primary to foot clutch and three-speed hand-shift gearbox; chain final drive; 48hp at 5800rpm CHASSIS/BODYWORK Silver-soldered cast/ tubular steel, diamond-style frame; girder fork; rigid rear; drum brakes; cast aluminium fuel/oil tanks; sprung saddle; weight 240kg (dry) BEST America’s fastest pre-WW2 production motorcycle; rarer than hen’s teeth NOT SO GREAT Rarer than hen’s teeth…

HONDA built on the world-changing success of the CB750 Four in 1969 not by going up in capacity but by going down, referencing the success of its small capacity multi-cylindered four-stroke GP racers of the early to mid-1960s. First off the rank was the CB500 in early 1972, like its older sibling a SOHC, two valves per cylinder, inline four making maybe 50hp at 9000rpm to the 750’s 68hp at 8500rpm. But it was around 25kg lighter and physically much smaller, which made it much easier to ride. The bore was stretched from 56mm to 58.5mm on the same 50.6mm stroke with the CB550 released two years later, initially as the conventionally styled CB550K which remained in production until 1978. From 1975 until 1977, a café-styled version, the CB550F Super…

ENGINE Air-cooled four-stroke boxer twin; OHV, two per cylinder; 94 x 70.6mm for 980cc; 9.5:1 comp; wet sump; 2 x Mikuni 38mm flat-slides; MMM Boxerworks ignition; dry single-plate clutch to five-speed gearbox; shaft final drive; 60hp at 6500rpm (stock) CHASSIS Twin-loop mainframe in tubular steel; fabricated sub-frame; GSX-R750 USD forks in Hyosung triple trees, dual 285mm BMW rotors with Brembo four-pots, laced 18-inch rim; mono-shock swingarm, drum brake laced to 17-inch rim; all fabrication by owner; Pirelli Sport Demon tyres BODYWORK Honda CB900 fuel tank; Suzuki TR750 seat; R65 mudguard; BMW F800 headlight; Daytona Velona speedo-tacho; paint and graphics by owner SPECIAL THANKS Chris Hodges, BM Shop Stafford; Spectre Vehicle Engineering; Ellaspede BEST Creative mix of models and parts; distinctive style; great handling and brakes NOT SO GREAT Not much…

I DO have a valid basis for assessing the worth of the Peckett triple, as the former owner of a pair of factory-built Rob North-framed BSA-3s, including the one that I raced in mid-'80s (750cc) World Championship TT Formula 1 rounds at circuits like Assen, Vila Real and the Isle of Man, plus the annual British GP support race at Silverstone. I have to admit it was a combination of bloody-mindedness and patriotism, coupled with appreciation for the triple's talents, that made me the last person ever to race a BSA motorcycle in World Championship competition, and to score points in doing so. But if I'd had the package that today’s RPS Triumph represents at my disposal back then, I'd have had an even more potent start money special for…

ENGINE Water-cooled two-stroke 50-degree V4; twin contra-rotating crankshafts with gear-driven balancer; reed-valve induction, with four transfer ports and a single exhaust port; 54 x 54mm for 494cc; 4 x 28mm Mikuni flat-slides; Yamaha CDI ignition; YPVS power-valve exhaust with expansion chambers; gear-driven primary to oil-bath clutch and six-speed cassette gearbox; chain final drive; 100+rwhp at 11,500rpm (est) CHASSIS Aluminium twin-spar mainframe with detachable sub-frame; fully adjustable 43mm USD forks, 2 x 320mm PFM cast-iron rotors with Tokico six-piston calipers on 17 x 3.5in Marchisini alloy wheel; modified GSX-R aluminium swingarm with Öhlins monoshock, single 190mm Yoyodyne titanium rotor with Brembo twin-piston caliper on 17 x 6in Marchisini alloy wheel; Dunlop D207 tyres BODYWORK Carbon-fibre YZR500 fairing, tank and seat; hand-fabricated controls; TZR250 switchgear; Avocet bicycle speedo DIMENSIONS Wheelbase 1375mm; dry…

ENGINE Air-cooled four-stroke single; OHV (two) operated by pullrods (see breakout); 39 x 40mm for 48cc; 6.25:1 comp; Weber MF14 carburettor with Biltwell Whiskey throttle; magneto/coil ignition; wet sump; two-speed transmission, chain final drive; 1.25hp at 5200rpm (claimed) CHASSIS/BODYWORK Pre-WW2 Iver Johnson bicycle frame; springer fork with hub brake; rigid rear with centre-pull rim brake; custom fuel tank in stainless steel; vintage Ideale seat; leather battery bag by Dane Utech; DENALI headlight; Ducati Monza paint; graphics by Artisimo BEST Style for miles; iconic engine; fuel economy NOT SO GREAT Motorways; long hills…

ENGINE Air-cooled four-stroke vertical twin, with 360-degree crankshaft; chain-driven SOHC, two valves per cylinder; 75 x 74mm for 653cc; wet sump; 2 x 34mm Mikuni carburettors; Pamco electronic ignition; custom fishtail exhausts; gear primary drive to Heiden clutch and five-speed gearbox; 520 chain final drive; 53hp at 7200rpm (stock) CHASSIS Much modified XS650 Special mainframe; modified P&P girder fork, XS400 TLS drum brake laced to 21 x 1.6in rim; extended swingarm, twin Harley shocks, XS650 SLS drum laced to 21 x 1.6in rim; all fabrication by owner; Pirelli MT43 tyres BODYWORK Custom fuel tank in 1.2mm sheet metal; cut-down aftermarket Harley fenders; vintage Triumph seat; all fabrication by owner; paint and graphics by Two Tones Autorefinish BEST Vintage flat-tank style; 100 per cent shed-built; soulful engine NOT SO GREAT Not…

motorcycle journalist and all-round top bloke Bob Guntrip has published a new book, Slow Burn, which traces the development of modified production bike racing in the decades leading up to the birth of the World Superbike Championship in 1988. The journey starts with Dick Mann’s 1970 Daytona 200 victory on a souped-up Honda Four, moves through the European Formula 750 and TT Formula 1 classes, and open class and Superbike racing in the US, and ends with the riders gridding up for what would become WorldSBK. Australia was a big part of the development of international Superbike racing, with quality fields in the keenly-contested Chesterfield Superbike Series, Shell Series and Victorian Superbike Championship. Riders included Graeme Crosby, Andrew ‘Ajay’ Johnson, Dennis Neill, Wayne Gardner, Mick Cole, Mal Campbell and the…

ENGINE Air-cooled four-stroke inline four; SOHC, two valves per cylinder; 58.5 x 50.6mm for 544cc; 9.0:1 comp; 4 x 22mm Keihin carburettors, with ram tubes; electronic ignition; Delkevic exhaust; chain primary drive to multi-plate clutch and five-speed gearbox; chain final drive; 50hp @ 8500rpm (stock) CHASSIS Double-cradle mainframe in tubular steel; fabricated seat sub-frame; shortened 35mm conventional forks, single 270mm disc brake on re-laced 19in DID rim; twin-shock swingarm, sls drum brake on 18-in DID rim; Coker tyres BODYWORK 1975 CB550K tank; custom seat unit; not much else; lots of chrome BEST Simple, elegant, perfect style and stance; strong engine NOT SO GREAT No instruments or guards…

ENGINE Air-cooled four-stroke inline triple; OHV, two per cylinder; 67 x 70mm for 740cc; 12:1 comp; dry sump; 3 x 33mm Amal Mk1 Concentrics; 12V Lucas Rita CDI; belt-drive primary to dry clutch and five-speed close-ratio gearbox; chain final drive; 55ft/lb at 7000rpm, 84rwhp at 8750rpm (measured) CHASSIS Chrome-moly tubular-steel twin-loop cradle; 35mm Ceriani forks, 2 x twin-piston Lockheed calipers on 254mm cast-iron rotors, laced 2.5 x 18in Akront alloy rim; fabricated steel swingarm with twin Koni shocks, single twin-piston Lockheed caliper on 230mm cast-iron rotor, laced 3.5 x 18in Akront rim; Avon AM22/AM23 tyres DIMENSIONS Wheelbase 1435mm; weight 165kg (oil, no fuel) BEST Smooth, fast, great sound; all but unbeatable in Classic F750 racing NOT SO GREAT Ordinary brakes…

WHEN we think of legendary engineers, names like Edward Turner, Phil Irving and Fabio Taglioni spring to mind. Well, here’s another, Shoichiro Irimajiri. A graduate in aeronautical engineering, 24-year-old Irimajiri was tasked in 1964 by Soichiro Honda to build a four-stroke 250 GP bike capable of beating the dominant two-strokes. The solution lay in more revs, and so Irimajiri designed not only a miniaturised inline six, he filled it with double-overhead cams and four tiny valves in each 41cc cylinder to make some 62hp. “We were up against four-cylinder two-strokes built by Yamaha and Suzuki,” Irimajiri recalled at the launch of the CBX1000. “Cylinder multiplication was the only way we could be competitive.” The new engine debuted in mid-1965, but overpowered the existing chassis and wasn’t immediately successful. Hailwood returned…

ENGINE Air-cooled four-stroke 75-degree V-twin; SOHC, two valves per cylinder; 92 x 69.2mm for 920cc; 8.3:1 comp; 2 x 40mm Hitachi carburettors with K&N filters; electronic ignition; custom exhaust; five-speed gearbox with shaft final drive; 65hp @ 6500rpm (stock) CHASSIS Box-section pressed-steel mainframe with engine suspended beneath; Kawasaki ZX6R USD forks, 2 x four-spot Tokico calipers and 310mm wave rotors, 17in cast wheel; triangulated cantilever-style swingarm with Sachs mono-shock, stock Virago drum brake and 16in cast wheel; Metzeler tyres BODYWORK Repositioned fuel tank; custom seat; not much else BEST Style in spades; aggressive stance; adjustable suspension; great brakes; soulful V-twin engine NOT SO GREAT Bold tyre lettering not for all…

ENGINE Liquid-cooled four-stroke inline six; chain-driven DOHC, two valves per cylinder; 62 x 71mm for 1286cc; 9.9:1 comp; wet sump; digital fuel injection; electronic ignition; Hy-Vo chain primary drive to five-speed gearbox; shaft final drive; 130hp at 8000rpm (claimed) CHASSIS Double-cradle mainframe in tubular steel; welded-on seat sub-frame; 41mm conventional forks, twin discs, 18-inch cast wheel; twin-shock swingarm, single disc, 17-inch cast wheel DIMENSIONS Wheelbase 1580mm; dry weight 297kg (327kg wet); seat height 835mm; fuel capacity 27 litres SPECIAL THANKS Wilco Vonk BEST Bigger is better; effortless smooth power; won’t mistake it for anything else NOT SO GREAT Likes a drink…

THOUGH I am not given to paranoia about governments snooping into our private lives, let it be known here and now that as far as I am concerned, what you do within the privacy of your own crash helmet is your own damn business. Me, sometimes I like to sing. That said, few other people who have heard me sing like to hear me sing. As an act of mercy towards all my friends (and complete strangers), I have never been to a karaoke bar. “Helmets are wonderfully solitary places. I like them that way” I’m not a bathroom shower singer, either. I’m just a crash helmet crooner, and my repertoire ranges far, wide and badly. Now I don’t sing inside my crash helmet all the time, just when the…