Reinforced Crankcase for Vespa Largeframe Models. It offers a durable base with potential for sporty everyday engines through to high-tech racers.
The backbone of every Engine is its Casing. Although it is only secondarily responsible for the performance of the unit, no Engine can be permanently stronger than its Casing allows. The load capacity of a Crankcase determines how much power the transmission can transfer from the Engine to the road. The installation space of the Casing determines how strong the parts mounted in it can be, i.e. how much force they can absorb. The design of the crankcase and cylinder sealing surface determine how far the limits for engine tuning are set
The SIP-BFA Casing redefines the limits of what is possible for the Vespa Largeframe Models. They are only redefined within an impressively wide frame. A displacement of up to 306cc is now possible. The power limit is pushed far beyond the 60 hp mark. Gearbox, Clutch and Crankshaft are guided precisely and extremely stable.
- Plenty of space for modern, high-performance tuning components.
- A solid, stable and elaborately balanced Crankshaft
- Very stable Casing, manufactured with extremely tight tolerances
The basic design and power transmission of the Engine is based on the original from PIAGGIO. The shaft spacing remains unchanged. All transmission components are compatible with those of the Vespa Engines. BFA has created a lot of space around this basic shape. Space for a larger Crankshaft, which can withstand the Elevation loads and, with its mass of over 3.5 kg, makes the Engine run more smoothly.
The right space for every Cylinder
More space is also available for the Cylinder. The ideal solution is the 306cc BFA Cylinder. Its performance potential is almost inexhaustible. The Engine and its components are already matched to the Cylinder and with its design for the original blower cooling it is easy to work with.
The generous space available for the Cranks and Cylinder naturally results in less space elsewhere. The BFA Engine is approx. 20mm wider than the original Casing. This means that the installation of the Side Panels requires some reworking, depending on the Model.
Depending on the model, original Vespa tuning cylinders and also many third-party cylinders with higher performance potential can be fitted. There is more than enough installation space. Even very expansive transfer ports can be accommodated. The cylinder base sealing surface measures 140x130mm.
A particularly positive feature of the design of the SIP-BFA Casing is the solid Seating for the Input Shaft. The inlet into the Crankcase sits directly transversely under the cylinder base, extends over both halves of the housing and offers 70mm of space for the Reed Valve. The use of the original SI Carburettor is no longer intended. Dell'Orto VHSB Carburettors fit best in the existing installation space. A sufficient supply of fuel can be ensured with the standard Vacuum Connection for a Fuel Pump. The two crankshaft bearings have an outer diameter of 62 mm and a width of 16 mm. On the clutch side, the Crankshaft is guided by a cylindrical roller bearing, the fixed bearing sits under the Ignition.
We offer the SIP-BFA Crankcase in two versions:
- 306: The Casing is prepared for mounting the 306cc BFA Cylinder and the corresponding 64mm stroke Crankshaft. Spacing of the BFA Studs: 100mm x 100mm. (Item no. 78245500)
- MALOSSI 221: The Casing is designed for mounting the Malossi 221 Cylinder, the transfer ports are already incorporated. Casing with the original cylinder stud spacing of the PX 200. For BFA Crankshaft with 60mm stroke. (Art. no. 78242100)
Note: Any desired or dreamed-of Engine can be achieved with the SIP-BFA Crankcase. With such extensive modifications and improvements, building the Engine requires some know-how and experience. We therefore ask you to read the instructions carefully before ordering and to go through the lists of scope of delivery and recommended parts in detail.
Not all Ignitions will fit on the Casing for the BFA 306, as the transfer ports are very protruding. We offer a modified Vape Fan (item no. 51007320), as well as a complete SIP Perfromance Ignition for this Engine (e.g. item no. 51007BSA).
Conclusion: A Crankcase that leaves nothing to be desired. The limits are now set by the chassis and brakes, not the potential of the Engine.
The following parts are included in the scope of delivery:
- Rear Abutment Cable Brake with Screws
- Rear Abutment Cable Clutch with Screws
- Screw Dust Cover
- Dustor Boxes Housing Halves
- Cover Sheet Fan Duct with Screws
- Bolts Brake Shoe
- Bushes Input Shaft with Screws
- Dustor Box
- Bushing Cylinder with Nuts
- Screws
- Crankcase
The best setup - our SIP-TIP:
- SIP BFA Crankshaft Art. no. 78245800, 78245810 or 78245820 absolutely necessary
- The SIP-BFA Clutch (e.g. item no. 78245922) is perfect for transmitting and metering power
- The Motorino Diavolo gearshift is a useful addition to a reliable high-performance motor (item no. 87049300).
- Best combined with the SIP Gear Pulley (art. no. 13978640).
Limited Edition
The BFA 306 Crankcases and complete Tuning Kits are produced in limited small series. The components come exclusively from Italian workshops specializing in tuning. Many work steps are necessary for these high-tech products. The effort involved is high. For this reason, we only decide on a new edition once a series in stock has been sold off.
However, we always have sufficient cylinders, Crankshafts, Clutches and wear parts in stock.
