MotoForce Racing 70cc Cast Iron Cylinder Kit – Minarelli Vertical AC (Yamaha BW’s / MBK Booster / and more)

The MotoForce Racing 70cc cast iron cylinder kit is the perfect upgrade for everyday riders who want more power and torque without sacrificing reliability. Designed for 50cc scooters with Minarelli vertical AC engines, such as the Yamaha BW’s or MBK Booster, it’s an ideal replacement for the stock cylinder that delivers real performance gains at a great price.

Constructed from durable cast iron, the cylinder features 5 transfer ports, a single oval exhaust port, a 47 mm two-ring piston, and a high-compression cylinder head. Depending on setup, the kit produces around 6–9 hp and offers strong torque with great throttle response — perfect for quick starts and smooth acceleration without stressing the engine at high revs.

Recommended setup :

• Minimum 17.5 mm carburetor

• Tuning CVT system

• Sport exhaust (e.g. Stage6 Pro Replica)

Specifications :

• 70cc cast iron cylinder (47 mm bore)

• Two-ring piston

• High-compression cylinder head

• For Minarelli vertical AC engines (Yamaha BW’s, MBK Booster, etc.)

• Not homologated / not street legal