BFA/FRT 165 cc High-End Tuning Cylinder for Vespa Small Frame 80–125 cc – Ø64 mm, 51 mm stroke, 105 mm connecting rod, direct intake with diaphragm and 3-piece exhaust.
The BFA/FRT 165 cc brings the high-displacement BFA/FRT small-frame concept to a more compact displacement class. With a 64 mm bore, 51 mm stroke, and 105 mm connecting rod length, this powerful direct-intake cylinder is designed for Vespa Smallframe engines in the 80 to 125 cc range.
An aluminum cylinder, five transfer ports, a three-piece exhaust port, and the included diaphragm form the basis for a performance-oriented yet versatile engine configuration. The cylinder head is included in the package, and the spark plug is centrally located in the combustion chamber.
165 ccm Ø64 mm 51 mm stroke 105 mm connecting rod 5 over-flow ports 3-piece exhaust Direct-inlet diaphragm
The 165-cm³ version is designed for Vespa Smallframe engines in the 80- to 125-cc class. Compared to classic Smallframe cylinders, it offers significantly more displacement and thus provides an excellent foundation for high-torque and high-performance engine designs.
As is typical with large-displacement Smallframe cylinders, the engine case, cylinder mount, transfer port, and crankshaft clearance must be compatible with the chosen configuration. Suitable BFA engine cases can be used as a base; alternatively, depending on the version, VMC engine cases or appropriately modified original Piaggio small-frame cases can also be used.
The 165-cm³ version is designed for a crankshaft with a 51-mm stroke and a 105-mm connecting rod length. This combination is part of the specific geometry of the 165-cc cylinder and distinguishes it from the 180-cc version, which has a longer stroke and a longer connecting rod.
The aluminum cylinder features five overflow channels. Intake occurs directly through a diaphragm into the cylinder and is therefore independent of a conventional rotary valve control mechanism in the engine housing.
The intake manifold and diaphragm are included in the scope of delivery. This means that the essential intake components required for assembly are already available and compatible with the cylinder.
The 165-cm³ version features a three-part exhaust. In addition to the central main exhaust port, additional exhaust ports provide a larger effective exhaust area.
This design enables a performance-oriented configuration without having to rely solely on an extremely wide main exhaust port.
The cylinder is made of aluminum. The material’s low weight and good thermal conductivity are important design advantages, particularly for high-performance air-cooled two-stroke engines.
The piston operates with a single piston ring and a 15 mm diameter piston pin. The single-ring design reduces the friction surface and is typical of performance-oriented cylinder designs.
The spark plug is centrally located in the cylinder head. An NGK B9ES spark plug is recommended.
| Recommended spark plug | NGK B9ES |
|---|---|
| Recommended ignition timing | 18° before TDC |
For the BFA/FRT 165, a compatible BFA engine case is the ideal foundation. Alternatively, depending on the configuration, the cylinder can also be combined with a VMC engine case or a suitably modified original Piaggio Smallframe engine case.
| Manufacturer | BFA Motori / FRT Racing |
|---|---|
| Engine Type | Vespa Smallframe 80–125 cc |
| Displacement Class | 165 cc |
| Material | Aluminum |
| Bore | Ø64 mm |
| Stroke | 51 mm |
| Connecting rod length | 105 mm |
| Piston rings | 1 |
| Piston pin | Ø15 mm |
| Overflow valve | 5 |
| Inlet | Direct inlet with diaphragm |
| Outlet | 3-piece |
| Cylinder head | Included |
| Spark plug position | Center |
| Recommended spark plug | NGK B9ES |
| Recommended ignition timing | 18° before TDC |
The BFA/FRT 165 is a high-performance tuning cylinder. The cylinder kit does not include general approval for use on public roads; applicable regulations and the possibility of individual approval must be verified prior to use.
The BFA/FRT 165 is the more compact version of the high-displacement BFA/FRT Smallframe concept. With a 64 mm bore, 51 mm stroke, and 105 mm connecting rod, it combines a large displacement with a cylinder architecture clearly designed for performance.
Five over-the-top valves, direct intake with a diaphragm, and the three-piece exhaust system create an interesting foundation for powerful street, touring, and sport engines. Matching BFA engine cases serve as the obvious foundation; alternatively, VMC cases or appropriately prepared original Piaggio cases can also be used.
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