Moto Morini 3½  Sport

3½GT Strada Classic

Model history

The Morini 3½ still has a loyal following and a number of spare parts are available from specialist firms. The former editor of Classic Bike magazine, veteran motorcycle writer Hugo Wilson, has owned a 3½ Sport since 1982 and still uses it as a regular commuter motorbike.[10]

The engine featured Heron heads,[11] which were milled flat and the combustion chamber is recessed in the piston crown, aiding combustion and returning excellent fuel economy. A fuel consumption test by Motorcycling Monthly at Britain's Motor Industry Research Association in 1976 returned a performance of 65 miles per imperial gallon (4.3 L/100 km; 54 mpg-US) while a 3½ bike carried rider and pillion passenger.[12] The engine also incorporated one piece forged steel crankshaft, ball main bearings (first series motors), plain big end bearings (second series motors), and the conrods run on a common pin, desaxe, and offsetting the rear cylinder to the front by 50 mm (2.0 in). Front and rear barrels and heads are interchangeable. VBH Dell'Orto (25 mm VHB 25 BS) square slide carburettors were fitted to the 350, with air fed via air-box with two filters.[11] Bore and stroke was 62 mm × 57 mm (2.4 in × 2.2 in), respectively.[11] The camshaft was driven by a small toothed belt, and was a revolutionary advance. They also included an electronic capacitor discharge ignition system designed by Ducati Elettronica. Early models had kick-start only but later ones also included a starter motor using three centrifugal friction shoes engaging the alternator rotor cover. The CDI ignition was powered by a coil in the alternator and using the kick-start a bike could be started and ridden with a flat battery.
Moto Morini 3½
Moto Morini 350 K2 1986

The frame is a full steel duplex swingarm design, with Ceriani rear suspension, and Marzocchi front forks.[11] The early models had a twin leading shoe drum brake up front (Strada: 200 mm (7.9 in) drum, Sport: 230 mm (9.1 in) drum) that was notoriously grabby on the Borrani spoked wheels, but these were replaced with a single chromed 260 mm (10.2 in) Grimeca disc in 1976, and later optional double discs. The rear drum brake was replaced in the early 1980s with a Grimeca disc. Switchgear, tail and brake lights were the standard CEV model used on many Italian motorcycles of the 1970s. The month and year of manufacture is embossed in small figures on the side of each cast wheel, near where one of the seven cast spokes meets the rim. The helical gear transmission was a six-speed, with top gear ratio of 1:0.954 made it an overdrive.[11] The transmission was engaged with a six-plate dry clutch, making a characteristic rattle similar to Ducatis when disengaged. Secondary drive was by a 5/8 x 3/8-inch chain to a rear sprocket with cush drive.[11] Gear change is by right foot and rear brake operated by the left foot. Engine lubrication was by oil pump to the crankshaft but no force lubrication went to the rocker gear. Instead, crankcase pressure forced oil mist up the short pushrod tunnels to the rocker covers, where two 'crow's feet' allowed mist to condense and drip onto the rocker gear. Although ingenious, it required riders to gentle warm up their engines before using maximum revs, redlined at 9,200 rpm. Oil filtration was by plastic mesh filter.

The 1979 model incorporated a moulded tank-hugging seat, black crankcase side covers and black exhaust system in homage to the Moto Guzzi Le Mans.

Footrests were placed too far forward for many riders and a common modification was to replace them with rearsets. Although not suitable for large riders, the 3½ was renowned for sharp and impeccable handling and was able to compete against larger capacity motorbike on twisty roads. Maximum torque was above 6,000 rpm and so required high revving, similar to a two-stroke, to make the most of the engine's characteristics. Nevertheless, a 3½ Sport could still return 70 miles per imperial gallon (4.0 L/100 km; 58 mpg-US) when ridden hard. The 3½ Sport had a higher compression ratio than the softer tuned Strada. The Sport featured Tomaselli clip-ons handlebars and throttle, steering damper and Veglia instruments.

In November 1981 a 500 Turbo was shown at the Milan Show, producing 84 bhp (63 kW) at 8,300 rpm. It did not make it to production. An enduro version called the Camel 500 was released in 1981. In 1983 the Kanguro 350 was released.

In 1986 Moto Morini brought out a cruiser version, the Excalibur, available in 350 and 500 versions.

The 350 was conceived as a modular design, and single cylinder versions were made. (Looking like the V-twin with the rear cylinder removed) These were the 1975 six-speed 125 H and the 1978 250 T Mono, both unsuccessful, as was the later KJ 125 single of 1985.[13]
350 performance figures

Strada 35 PS (26 kW; 35 hp) at 8,600 rpm
Sport 38 PS (28 kW; 37 hp) at 8,500 rpm, 32 ft·lbf (43 N·m) at 5,100 rpm.

500 performance figures

46 hp at 7,500 rpm

Source Wikipedia