Cylinder Head Stage6 BigRacing / Streetrace 77cc Derbi Euro 2

Stage6 BigRacing cylinder

The Big Racing cylinders are extremely powerful cylinders for 50cc supermotos. Although they are very powerful high-end cylinders, they offer a good balance of performance and reliability for intensive, regular, even daily use.

The aluminium cylinders have a displacement of 77 to 88 cc (with the corresponding crankshaft ) and were mainly developed for 50cc motorcycles with Derbi and AM6 engine, e.g. Rieju MRT, Beta RR or Sherco.

In combination with a suitable exhaust, a complete intake system and a suitable gearbox, the BigRacing can achieve maximum power with maximum torque and increased top speed.

The Stage6 R/T series delivers even more power, with uncompromising performance for use on the race track.

technical data :

• Aluminium cylinder
• 1-ring piston
• Original big bore design (not simply opened up)
• Transfer ports and compression designed for maximum reliability
• 77cc displacement for crankshaft with original stroke
• 86cc or 88cc cylinder for long stroke crankshaft
• One-piece cylinder head
• Discreet design with 49ccm lettering
• Also available as a kit with exhaust or crankshaft
• All spare parts available separately (pistons, gaskets)

Stage6 Streetrace

As the name suggests, the Streetrace series was developed for sporty street use. The Stage6 series includes cylinders and exhausts that deliver relatively high performance, but still function reliably in everyday use.

The Stage6 Streetrace series feature the optimum balance between performance and durability to offer scooter and supermoto riders a high level of riding enjoyment even in everyday use.

Cylinder head

The cylinder head of an internal combustion engine can have different shapes and contain different elements, depending on the type of engine. While in a two-stroke engine the cylinder head contains only the spark plug, in a four-stroke engine it is much more complex, as it also contains the valves, the camshaft and many other parts that are important for the operation of a 4-stroke engine.

However, these two points apply to any cylinder head:

• it must be tight
• it controls compression

Different types of cylinder heads

Each cylinder head is specifically designed for a specific cylinder. You must therefore always make sure that the cylinder head fits the cylinder.

Cooling :

The cylinder head is also partially responsible for cooling the engine. In air-cooled engines it has fins on the outside and in liquid-cooled engines there is chamber for the circulating coolant.

One-piece or two-piece 2-stroke cylinder head

One-piece cylinder heads are the most common, but modular two-piece cylinder heads are also available for 2-stroke engines. The principle is quite simple: the water jacket allows water circulation, while the combustion chamber insert closes off the combustion chamber. The cylinder head can be replaced and modified to achieve different compression ratios and thus different engine behavior.

4-stroke cylinder head

Tuning cylinder heads can also be found for four-stroke engines. Although components optimized for motocross are seldom found on the market (usually they are original components that have been reconditioned to increase performance), there are also racing cylinder heads for scooters and motorcycles. These often have optimized intake and exhaust ports and sometimes even seats for larger valves.