Ducati 851

Ducati 851

Manufacturer	Ducati
Production	1987-1992
Successor	Ducati 888
Class	Sport bike
Engine	851 cc (52 cu in), L-twin, fuel injected 4 valves per cylinder desmodromic, liquid cooled bore/stroke: 92.0 × 64.0 mm (3.6 × 2.5 in) Compression ratio: 10.0:1
Power	93.00 hp (67.9 kW)) @ 9600 rpm
Transmission	6 speed, chain drive
Frame type	Tubular steel trellis frame
Brakes	Front: Dual disc Rear: Single disc
Tires	Front: 120/70-17 Rear: 180/55-17
Weight	~430 lb (200 kg) (dry) ~460 lb (210 kg) (wet)
Fuel capacity	20 litres (5.3 US gal)

The Ducati 851 was a Ducati motorcycle, with liquid cooling and four valve heads, released to the public in 1987. Development had lagged with the continued use of two valve engines, but new funds enabled a technological move forward Ducati needed at the time.^[1][2]

Ducati 851

After buying Ducati, Cagiva invested in the development of another V-twin, but with liquid cooling, and four-valve desmodromic heads. Massimo Bordi had designed a 4V Desmo in 1973 for his thesis at the University of Bologna, and with Cagiva in 1985, saw his updated ideas come into production as the Desmoquattro.

Based on the Pantah motor, but with liquid cooling, fuel injection, and desmodromic four valve heads (with an included valve angle of 40°), the 851 made Ducati once again competitive in motorcycle racing.

The original Desmo Quattro was an experimental 748 cc 4 valve racer (seen at the Bol d'Or in 1986) and used 750 F1 Pantah crankcases. Bordi collaborated with Cosworth to develop the heads, but in the time they had, they were only able to reduce the included valve angle of the desmodromic engine to 40°, while less than 30° was possible with valve springs. Ducati stuck with the desmodromics.^[3]

The subsequent 851 road bike had stronger crankcases, while the heads and valves remained the same; designed to fit above the 88 mm bore of a 748 cc version.

The 1987 – 1988 Ducati 851 Strada used the signature steel tube trellis frame, adorned with Marvic wheels, Brembo brakes and Marzocchi suspension. That first release was criticised for its handling, so the front wheel was changed from a 16 inch to a 17 inch (41 to 43 cm) wheel. In addition, upgraded suspension components were fitted.

In 1992 the bore was enlarged, thus creating the Ducati 888.^[4]

Three 1992 Ducati Superbike models were available: the 851 Strada (851 cc), the 888 SP4 (888 cc) and the 888 SP4S (888 cc).

Racing

• 1986 Marco Lucchinelli - Ducati 851 (Pole Position, Misano GP)^[5]

• 1987 Marco Lucchinelli - Ducati 851 (Pole Position, SBK)^[6]

• 1990 Raymond Roche - Ducati 851 SBK (World Champion, SBK)^[7]

References

1. ^ "Ducati 851". Diseno. http://www.diseno-art.com/encyclopedia/vehicles/road/bikes/Ducati_851.html. Retrieved 2006-11-05. 
2. ^ "Ducati Heritage: The 851". Ducati Motor Holding. http://www.ducati.com/heritage/anni80/851/caratteristiche.jhtml. Retrieved 2008-06-22. 
3. ^ "The story of the 748 Quattrovalvole". SigmaPerformance. http://www.sigmaperformance.com/748-853.html. Retrieved 2006-11-05. 
4. ^ "'888 SBK specs". Ducati. http://www.ducati.com/heritage/anni90/888sbk92/caratteristiche.jhtml. Retrieved 2006-11-06. 
5. ^ "Ducati Heritage: The 851". Ducati Motor Holding. http://www.ducati.com/heritage/anni80/851/caratteristiche.jhtml. Retrieved 2008-06-22. 
6. ^ "Ducati Heritage: The 851". Ducati Motor Holding. http://www.ducati.com/heritage/anni80/851/caratteristiche.jhtml. Retrieved 2008-06-22. 
7. ^ "Ducati Heritage: The 851". http://www.ducati.com/heritage/anni90/851sbk/caratteristiche.jhtml. Retrieved 2008-06-22.