Big Bore Cylinder Kit with Head Ø 47,6 mm, Pin 10 mm, Flat Head Piston
WARNING: the cylinder head and base gaskets contained in the kit are specifically developed for Athena cylinders kits. Whenever the cylinder kit is disassembled, replace the gaskets with the specific Athena spare gasket kit: DO NOT use OE replacement gaskets.
Race Use Only Product – Not intended for street use – Please check details on the “Race use only” footer’s section
Description
Athena is pleased to announce an absolute novelty in the world of air cooled vertical Yamaha-Minarelli engines and therefore for legendary applications such as MBK Booster / Yamaha BW’s or the iconic Aprilia SR*.
With this brand new big bore cylinder kit, Athena R&D department brings on this cylinder technical solutions usually applied only on high performance engines, such as on the 2T Racing GPs. The multiple innovative technical solutions introduced in this project allow to reach performances never achieved before with this engine.
With this new cylinder kit Athena is introducing many solutions never seen before on these applications. The result is just the best performing cylinder kit ever designed in its category.
A REVOLUTION ON THE PORTS
Athena’s technicians wide experience in the 2T sector allowed them to approach this cylinder challenging the traditional design. The intake and exhaust ports have been totally redesigned: analyzing the thermo-fluid dynamics of the engine, overall performances have been highly improved in terms of power and torque, achieving new levels for the first time ever. The intake port is reinvented, adding a CNC machined fifth port to grant a higher gas flow incoming in the combustion chamber.
Using the innovative fixing system directly on the crankcase without using stud bolts, Athena developed an exhaust outlet with a bigger oval shape and side auxiliary ports. This solution has been applied for the first time ever on this kind of cylinders.
REINVENTED PATENTED FIXING SYSTEM
The regular head and cylinder tightening based on studs has been eliminated introducing a new system patented by Athena of special bolts pretty close to the ones used in the high-level performing engines. Tightening the cylinder to the crankcase (Racing type) with these bolts and a special Allen key leads to a reduction of the thermal expansion of the cylinder, bringing a more efficient tightening and on the other hand allows the sophisticated redesign of the exhaust port that makes this product so special and unique.
NEW RACING PISTON
The flat head piston has been developed focusing in particular on the interaction with the intake. The CNC machined opening on the piston skirt is designed to maximize the inlet flow, to allow greater pressure on the pump casing and better lubrication of the needle bearing.
Bullet points
Redesigned intake and exhaust ports
Redesigned piston to maximize inlet flow
Reinvented and Patented Athena fixing system
Technical features
| Bore Diameter (mm) | 47.60 |
| Compression Ratio | 13.8:1 |
| Displacement (cc) | 70.00 |
- Height: 12.50
- External Diameter (mm): 14.00
- Internal Diameter (mm): 10.00
- Manufacturer: ATHENA
- Net Weight (Kg): 0.00
- Net Weight (Kg): 0.04
- Compression Height (mm): 24.50
- Big End Pin Diameter (mm): 10x5x36
- Number Of Segments: 1
- Piston Type: Cast
- Net Weight (Kg): 0.31
- Compression Height (mm): 24.50
- Big End Pin Diameter (mm): 10x5x36
- Number Of Segments: 1
- Piston Type: Cast
- Compression Height (mm): 24.50
- Big End Pin Diameter (mm): 10x5x36
- Number Of Segments: 1
- Piston Type: Cast
- Compression Height (mm): 24.50
- Big End Pin Diameter (mm): 10x5x36
- Number Of Segments: 1
- Piston Type: Cast
- Manufacturer: ATHENA
- Net Weight (Kg): 0.06
- Oil Seal Total Height (mm): 11.00
- Oil Seal External Diameter (mm): 54.00
- Net Weight (Kg): 0.40
- Manufacturer: ATHENA
- Net Weight (Kg): 0.06
- Oil Seal Total Height (mm): 10.50
- Oil Seal External Diameter (mm): 53.00
- Manufacturer: SKF
- Net Weight (Kg): 0.05
- Oil Seal Total Height (mm): 9.00
- Dust Seal Total Height (mm): 4.90
- Manufacturer: ATHENA
- Net Weight (Kg): 0.05
- Oil Seal Total Height (mm): 10.50
- Oil Seal External Diameter (mm): 52.00
- Manufacturer: ATHENA
- Net Weight (Kg): 0.06
- Oil Seal Total Height (mm): 11.00
- Oil Seal External Diameter (mm): 50.00
- Manufacturer: ATHENA
- Net Weight (Kg): 0.05
- Oil Seal Total Height (mm): 9.50
- Oil Seal External Diameter (mm): 53.00
- Height: 14.80
- External Diameter (mm): 15.00
- Internal Diameter (mm): 12.00
- Manufacturer: ATHENA
Ireland 