Four stroke, 72° V-twin, OHV, 2
valves per cylinder.
Capacity
344 cc / 20.9 cu-in
Bore x Stroke
62 x 57 mm
Cooling System
Air cooled
Compression Ratio
11.0:1
Induction
2x 25mm Dell'Orto carburetors
Ignition
Electronic CDI
Starting
Kick
Max Power
39 hp / 28.5 kW @ 8500 rpm
Max Torque
33.6 Nm / 24.8 lb-ft @ 6300 rpm
Transmission
6 Speed
Final Drive
Chain
Frame
steel twin loop
Front Suspension
32mm Telehydraulic forks
Rear Suspension
Swinging arm dual adjustable shocks
Front Brakes
2x 254mm Discs
Rear Brakes
180mm Drum
Front Tyre
3.25-18
Rear Tyre
4.10-18
Wet Weight
160.0 kg / 352.7 lbs
Fuel Capacity
14 Litres / 3.7 US gal
Consumption Average
51 mpg
Standing
¼ Mile
15.3 sec / 83.2 mph/
Top Speed
97 mph
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.