Cycle News is a weekly magazine that covers all aspects of motorcycling including Supercross, Motocross and MotoGP as well as new motorcycles
Issue link: https://magazine.cyclenews.com/i/127716
Cagiva's 750cc F4 Superbike By Alan Cathcart here are no pri zes for guessing what prompted Cagiva to release these first official photos of their 750cc four-cylinder superbike engine, on . which the Italian factory's technical staff has been working wid e-open, ever since they stopped de velopment work back in July last yea r on the Italian company's bright-red 500cc V-fou r tw o-strokes. Their bitter rivals Aprilia sco re d a major publicit y coup by actually displa yin g th eir protot yp e s u pe r bi ke motor, a Rota x-built V-twin , a t the Bologna Show last Decembe r. Now, thou gh Ca giva d es ign chief Ma ssimo Tamburini is still hard at work fin alizing the chas sis design "of the first European 750cc fou r-cylinder motorcycle to be built since the MV Agusta glory da ys 20 years ago, prior to its launch at the Milan Show in November, Cagiva ha s been spurred to show us the final preproduction version of an engine which . has been under development since 1988. That was the year that Cagiva bosses Claudio and Gianfranco Castiglioni teamed up wit h their close friend Piero Ferrari - son of Ferrari owner Enzo - to dev.elop a four-cylinder motorcycle engine incorporating some aspects of Formula O ne technology borrowed from the works Ferrari racing car engines. Cagiva's collabora tion with T 16 Piero's Ferrari En gineerin g company has seen many concrete re sults since th en , m ost notabl y th e carbon-fib er cha ssis Ferrari desi gn ed for the 500cc Cagiva GP bik e in 1990, or the carbon sw ingarms John Kocinski raced with in ' 93 and ' 94. But the four-cylinder fou rstro ke engine has seen m any different versions built ov er the past six years, e ach incorporatin g rad ical d esign aspects which d istingui shed the con cept from the universal Jap anese mot orcycle in -line-four desi gn, but w h ic h h a ve largely been discarded in the final version pictured here. These cha nges a re reput ed to ha ve included a reversed cylinder head with forwa rd -facin g in le t a n d rear-facin g exhausts (rejected becau se of the difficulty of installing an airbo x, as well as optimum exhaust len gth ); variable valve tim in g; five valves ,per cy li nd er; and, most remarkabl y, offset cylinder bores to reduce en gine width as mu ch as possible, resulting in wh at wa s effectivel y a very narrow-angle (about 15 degrees) Vfour. The final F4 (Ferrari fourcylinder / s t ro k e ) Cagiva s u p e rb ik e engine shown here embodies none of these radical - in two -wheeled terms design features, bu t it does have specifica tions differing in se vera l key areas from the products of Japan, Inc. Unlike any of its current four-cylinder rivals, the Cagiva F4 is dry-sumped, indi cating i ts racing heritage, u s e s Weber / Marelli electronic fuel injection, and has fou r radial val ves per cylinder, with double overhead camshafts driven b y a centrally lo ca te d chain. Ferrari Enginee ring's contribution to the design is understood to relate mainly to the cylinder head, whose radial valve layout follows current Ferrari F-1 race engine practice. Interestingly, Ferrari is known to have ex peri mented with desmodromic valve gear on their F-1 engine two years ago, bu t it's not known if the F4 tw owheeled design ever shared this design feature with its Ducati .cou sins in th e Cagiva group. And judging by the relatively shallow rocker boxes, it certainly doesn't have it now because there's no space for all the extra rockers needed . However, the fo rward til t to th e cam cover seems to indicate lon ger in take