RB25 cylinder 250 cc from AF for Lambretta
Bore 72 mm, stroke 60 mm, Nikasil-coated aluminum cylinder. Timing: Exhaust 182°, transfer port 128°, intake diaphragm-controlled, advance 27°.
With the RB25 kit, the tried-and-tested TS1 cylinder from AF has been given a superior brother in terms of performance and displacement. The cylinder layout is clearly inspired by the MotoX range. The intake is controlled by two very wide 4-flap diaphragms. The arrangement of the diaphragms results in a V shape. Ducts lead directly from the inlet duct into the transfer ports, and there is also a boost port. The surface area of the outlet has been enlarged by two secondary outlet ducts.
The piston used is a modified ASSO forged piston from the Rapido 250 with two thin 1 mm chrome rings. The RB 250 is designed for a crankshaft with a 60 mm stroke. To prevent the cylinder base from becoming too thin with the 72 mm piston, it is larger in diameter. The engine housing must be spindled accordingly in order to install the cylinder. The stud bolts do not have to be offset.
In addition to the cylinder and the piston, the scope of delivery also includes the diaphragm and the intake manifold.
In terms of workmanship, it cannot yet hold a candle to the TS1 produced by the Italian top foundry Gilardoni. Neither in terms of casting nor coating quality.
DE | €
