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Motobi SportSpecial 250

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After the unification of Benelli and MotoBi, which took place in 1962, models derived from the " Imperiale " remained in the list and were marketed simultaneously with both brands.

The "Sport Special" model was the last to mount the single-cylinder egg designed in 1956 by Piero Prampolini , for the first time equipped with a 5-speed gearbox. Its accomplishment was decided in 1967 to try to recover market share, particularly in the eighth of a liter, following the great success of the Gilera 124 5V , presented in the previous year .
The bike

Released at the end of 1968 (initially with the only MotoBi brand, followed by a growing percentage also with the Benelli brand), the first series of "Sport Special" resumed the technical setting of the "Imperiale" with the upper chassis in sheet metal (red or black). The attention of the technicians was aimed at making the vehicle slim and compact. From the start, the motorcycle was offered in the two 125 and 250 cm³ engines, visually recognizable only by the colors: silver and red for "125", silver and yellow for the "250". This first series was standard equipped with low-setting sports headdresses.

At its launch, the "Sport Special", in particular in the 125th Cylinder, was probably the most powerful of the respective category (in the wake of a tradition that saw MotoBi dominate the junior race championships for over 15 years, conquering over 2000 wins in classes 125, 175 and 250). The public welcomed the model, although the interest in road and four-stroke engines was rapidly falling, blurred as they were from two-stroke off-road SUVs that dominated the motorcycle market for all the years seventy .

At the beginning of 1971 , the second series of "Sport Special" was introduced, which maintained the line and the mechanics unchanged, benefiting from the new Marzocchi trimmed fork and monochrome colors, blue, red, green, gray and bronze. The bike was now supplied standard with higher semimanububs and equipped with an adjustable "bracelet" mount that allowed for a more touristy driving position, probably more suited to the unchanged position of the pedal controls. The number of specimens produced by the Motobi brand was at this point a small fraction of the total: the vast majority ran the Benelli brand.

At the Milan Motor Show in November 1971, the 3rd and final series was modernized by a new saddle, a slimmer, less squared tank (as well as smaller) with a chromed lower profile, a new chrome front headlight and tachometer instrumentation. Another characteristic feature of this series was the head of the head of square rather than rounded shape. The colors, always metallized, were blue, red, green, yellow and bronze.

The "Special Sport" came out of production at the end of 1973 , after about 20,000 manufactured specimens, of which 70% in the "125" and 80% branded Benelli brand.
Curiosity

The list price of the "125" in 1968 was 215,000 Lire, in 1972 it reached 311,000 Lire.
The builder did not emphasize the performance of the standard engine on the advertising brochures : for example, the "125" was declared a power at the 10-hp shaft when it actually developed almost 12.5 on the wheel.
As an alternative to the standard semimanububs, it was provided by the house with a horizontal joining crossbar, more convenient but not in tune with the general aesthetics of the vehicle.
In accordance with the sporty design of the model, the carburettor was fitted with a series of suction filter without filter, although a circular air filter was available on request.
The "Sport Special" was equipped with a 6 V and 8 Ah battery, but the ignition (coil / spark plug) and the headlamp (dazzle / glare) were powered directly by a winding wagon; the battery used to power the position lights, stop light, and the horn. To access the battery, it was necessary to remove the saddle.
Among the enthusiasts were very popular the production kits marketed by Primo Zanzani (former technical director of the MotoBi racing department). The car kit, available for both "125" and "250" at a price of 63,000 Lire (in 1970), included a camshaft and a different piston, chrome plungers and a modified gearbox. The "125" was 16.5 hp at 10.800 rpm for 140 km / h of maximum speed (virtually the performance of the "250" series). A 70,000 Lire was available with a chassis kit including chassis reinforcements, backrests, swingarms and bushings. The aluminum racing tank was sold at 28,000 Lire.

Technical data
MotoBi Sport Special 250 1st Series
MotoBi Sport Special 125 2nd Series
Benelli Sport Special 250 3rd Series
Data Sport Special 125 Sport Special 250
Engine : 4-stroke mono-cylinder horizontal 54x54 mm 123.6 cm³ 74x57 mm 245.1 cm³
Compression ratio: 9.2: 1 8.5: 1
Power and regime: 12.5 hp at 8.500 rpm 16.5 hp at 7,500 rpm
Cylinder Head: in light alloy
Valve Position: in the head, inclined by 60 °
Valve control: to rods and barbells
Ignition: magnet flywheel with external AT coil
Carburettor : Of the Orb UB22BS Of the Orb UB24BS2
Lubrication: forced with gear pump
Clutch: multiple oil bath discs
Change : in 5-way lock, pedal control
Transmission : primary to helical gears, secondary to chain
Chassis - step: upper cranksets with open cradle in sheet metal and steel tubes
Suspensions : with telescopic fork
Post suspensions: swinging swingarm with hydraulic shock absorbers
Wheels : 18 "steel spokes
Tires : ant. 18 "x2.75, post 18" x2.75 (125) -18 "x3.00 (250)
Brakes ( Drum ): A ∅ 175 mm - P 125 ∅ mm
Length: 1.940 mm
Width: 830 mm
Height: 970 mm
Saddle height: 710 mm
Step: 1.260 mm
Height min. from the ground: 150 mm
Gasoline Capacity: 12.5 liters (1st and 2nd Series) / 11 Liters (3rd Series)
Oil Cup Capacity: 2 kg
Dry weight: 103 kg 108 kg
Full speed: 130 km / h 140 km / h
Acceleration (400 m): 18 "9 -
Consumption: 2.6 liters x 100 km -
Sources

MotoBi Sport Special 125-250 - Road Test , Motorcycling , 4/1970 , Edisport , Milan
Comparative Test 125 , Motorcycling , 7/1973 , Edisport , Milan
Alberto Pasi, Benelli 125 Sport Special , Vintage Motorcycle Racing - 5/2002 , Edisport , Milan
Alberto Pasi, The Fastest , Vintage Motorcycle Racing - 7/2012 , Edisport , Milan

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Source wikipedia