66 mm bore, 58 mm stroke, nikasil-coated aluminium cylinder for the small crankcases with 125-175 cc. With the standard stroke of 58 mm you already have 200 cc.
Valve timings: transfer ports - 128°, intake ports: reed-controlled, Exhaust port - 190°, blow-down - 31°.
Although being the smallest kit in the RB series in terms of displacement, the RB20 still has a great cylinder layout. The reed intake with a Boyesen port also has three boost ports. The exhaust port is in one piece, thereby offering more space for future tuning procedures than the RB22 and RB25 kits. As for these two kits, the auxiliary exhaust ports limit any porting efforts.
AF provides the piston known from the GT 186 kit, however with a diameter of 66 mm in this case. Both steel piston rings are 1.2 mm thick. Compression height amounts to 30 mm, therefore a con-rod of 115 mm length is required.
Besides the cylinder, cylinder head and piston, the reed blocks and matching manifold are included in delivery.
To evaluate products you need to be logged in.