Cycle News - Archive Issues - 1980's

Cycle News 1984 11 21

Cycle News is a weekly magazine that covers all aspects of motorcycling including Supercross, Motocross and MotoGP as well as new motorcycles

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... - C \f l-o Q.) ..0 E Q.) :> (Above and belowl Two views of the 900: Compr..sion ratio is 10.8:1 from Wiaeco pistons; intake valves measure 44mm, exhaust valves 40mm; cam timing is 66°-90° intake with 12mm lift and 95°-56° exhaust with 11 mm',lift, me..ured at zero lift; external oil lin.. feed valve train. Leoni's 900 has a polished crankshaft with 75055 connecting rods, which are longer than stock 90055 rods. The Wiseco pistons have just two rings - one chromed compression, one three-piece oil control - and the crankcases are bored to 95mm to accept oversize cast iron cylinder liners. All the gears in the cam bevel drive are polished, and the bevel gears are shimmed - Leoni says they must be "free, not loose, not tight, but just free." A window in the rear cylinder's cam drive cover plate allows Leoni to tell when the Castrol R40 engine oil is warm enough for Adamo to ride the bike - cold oil collects and fills up the window, and when the oil's warm enough it's also thin enough that it drains quickly down the bevel shaft tube and doesn't fill the sight window. Hollow camshafts are fed oil through external lines fitted to the rocker covers; rockers are lubed through holes in the cam lobes. The crankshaft oiling system is also redone, routing oil through a Derale cooler and then to an aluminum block with three fittings, one to the crankshaft and one to each cylinder head, with 2.6mm restrictors in each cylinder head feed line to maintain crankshaft oil pressure. (Below) Adamo at speed on the 900, which has 300mm Srembo cast iron front discs and a 280mm aluminum rear disc; front calipers are fourpiston, quick-change Srembos; carbs are 41.6mm Maloni-modified Dell'Ortos; Leoni buih the two-into-one exhaust system. Rear shocks are 13.6-inch Fox Superbike 5hox, positioned by trial-and-error testing. Leoni's Pantah has the same type of external oiling syste'm as his 900, but feeds oil to the center of the polished crankshaft; connecting rods are Carrillo chrome-moly steel. The 41 mm intake valves are timed 60°-90°; 35mm exhausts 90°-60°. . o Z (Abovel Pantah has hydraulic dry clutch, close-ratio transmission and standard belt cam drive; ignition is battery-powered with Accel coils. (Abovel900's dry clutch is an early Ducati NCR (works) part, matched to an NC R close-ratio transmission; clutch cover comes from early Hailwood replica. (Selowllgnition rotor is drilled for lightness; note two pickups. 15

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