Stage6 R/T 70cc Cylinder Kit  - Derbi D50B0/D50B1

The cylinder that has been breaking records! It set new best times in the Italian Open Cup and also broke the 6-second barrier in scooter dragracing. 

Regarding transfer port layout, Stage6 has maintained GP standards, refraining from cross-section reducing 7- or 8-port designs. After all, “more” isn’t necessarily “better”. 

The 47.6 mm bore conforms to the rules of most 70cc racing classes. 

The patented modular construction allows for quickly mounting the cylinder to different engines using adaptors. Sealing between adaptor plate and cylinder is realized via a Viton® O-ring; this makes the tedious cleaning of sealing surfaces and replacing gaskets unnecessary. Once the adaptor plate has been mounted and adjusted via gaskets, it won’t have to be readjusted later. 

The CNC-milled adaptor plate bolts to the engine case and accepts the cylinder via the external studs. The construction of the R/T 70cc cylinder doesn’t use any continuous studs, so the design of exhaust and transfer ports isn’t subject to the restrictions that conventional racing cylinders face, and further tuning and porting reserves are available. 

Particular attention has also been paid to the cylinder’s thermal properties. The CNC-milled inner cylinder head is bolted at five points, each of them thermally stabilized by its own cooling pocket. Thus the critical areas at the studs that tend to lead to piston seizures have been eliminated. 

In order to mount this cylinder, you’ll have to open the engine case to 56.7mm. In case of faulty or missing mounting parts, please ONLY use Stage6 replacement parts to avoid irreparable damage. 

You’ll also need a crankshaft with 90mm conrod and 12mm piston pin.

Stage6 S6-7519303