Cylinder Kit Top Performances Due Plus 70cc cast iron Piaggio LC 9920590

<p>MMG Racing Store presents the <strong>70cc Evolution cast iron cylinder kit</strong>, diameter <strong>47mm</strong>, specially designed for scooters such as <strong>Aprilia SR 50, MBK Booster 50 or Yamaha Bw's manufactured from 2004 onwards, for example</strong>.</p> <p>Made from high-quality cast iron, this kit includes the cylinder, head, piston, <strong>12mm piston pin</strong>, as well as all necessary rings and gaskets. Reliable, it will allow you to improve your scooter’s performance.</p> <p>The Polini Evolution 70cc cast iron cylinder for Minarelli vertical engines (MBK Booster, Yamaha, etc.) is aimed at riders seeking a radical improvement in scooter performance. This <strong>12mm pin</strong> version is based on a very robust technical design, built to deliver top results in intensive sport use or even competition.<br /><br />Although made from cast iron, this kit breaks away from tradition. Polini has completely redesigned the thermal group, incorporating solutions usually reserved for higher-end engines. The result? More power, greater torque, and a punchier response throughout the rev range.<br /><br />One of its strong points is the reed valve box integrated directly into the cylinder, equipped with two additional ducts that feed the transfers directly. This increases the mixture load and improves low-end response. The pack also includes a 4-petal reed valve—much better than the traditional 2-petal type—and a 360° rotating manifold, compatible with Polini CP carburetors from 17 to 24 mm. Thanks to this, you can mount any filter you like without worrying about orientation or available space.<br /><br />With the right setup, this kit can reach up to 14 real HP, an impressive figure for a cast iron cylinder. The torque curve remains wide and steady, providing explosive acceleration and excellent speed retention over long distances.</p>

POLINI

<h2>Top Performances 85cc Engine Kit Minarelli AM6 – Cylinder + 44mm Stroke Crankshaft</h2> <p>The <strong>Top Performances 85cc engine kit for Minarelli AM6</strong> represents one of the most complete combinations of <strong>performance, reliability and durability</strong> among cast iron maxi kits. This set includes <strong>cylinder, piston and long-stroke crankshaft</strong>, offering a complete solution for high-level engine builds.</p> <p>The heart of the kit is its <strong>cast iron cylinder</strong> with a <strong>49.5 mm bore</strong>, fitted with a <strong>single-ring piston</strong> and a <strong>high-compression modular cylinder head</strong>. Combined with the <strong>44 mm long-stroke crankshaft</strong>, a final displacement of <strong>85cc</strong> is achieved, providing a very significant increase in torque and power.</p> <p>Thanks to its cast iron construction, this kit stands out for its <strong>high mechanical strength</strong> and ease of repair in case of seizure, a clear advantage over aluminium kits. Its <strong>bridge-less exhaust port</strong> and internal porting make it an ideal option for riders seeking serious performance without sacrificing robustness.</p> <p>With the proper setup, this kit can deliver approximately <strong>17–19 HP</strong>, and with larger racing carburetors and exhausts, it is capable of reaching much higher figures in advanced builds.</p> <h3>Installation recommendations</h3> <ul> <li>Minimum recommended carburetor: <strong>21 mm</strong></li> <li>Recommended exhausts: <strong>competition / racing</strong> (Yasuni R3, Pro Race, SCR Racing Line, etc.)</li> <li><strong>Attention:</strong> as this kit uses a <strong>44 mm stroke crankshaft</strong>, it may be necessary to <strong>machine the inside of the crankcases</strong> for correct installation.</li> </ul> <h3>Technical data</h3> <ul> <li><strong>Displacement:</strong> 85cc</li> <li><strong>Piston diameter:</strong> 49.5 mm</li> <li><strong>Cylinder material:</strong> Cast iron</li> <li><strong>Piston:</strong> 1 ring</li> <li><strong>Crankshaft stroke:</strong> 44 mm</li> <li><strong>Exhaust timing:</strong> 191°</li> <li><strong>Intake timing:</strong> 132°</li> <li><strong>Squish clearance:</strong> 0.9 ± 0.1 mm</li> <li><strong>Compression ratio:</strong> 8:1</li> <li><strong>Recommended ignition timing:</strong> 17° (1 mm before TDC)</li> <li><strong>Recommended spark plug:</strong> NGK BR10EG</li> </ul> <h3>Top Performances 85cc AM6 maxi kit contents</h3> <ul> <li>Top Performances 85cc cast iron cylinder</li> <li>Piston</li> <li>Needle bearing</li> <li>Modular cylinder head / combustion chamber insert</li> <li>Water plug</li> <li>Complete gasket set</li> <li>Reducer sleeve 28 / 25 mm</li> <li>44 mm long-stroke crankshaft</li> </ul> <p>A <strong>high-performance maxi kit</strong>, designed for those who want to transform their AM6 into an extremely powerful engine while maintaining the reliability that characterizes <strong>Top Performances</strong> products.</p>

TOP PERFORMANCES

METRAKIT

<h2>Metrakit Pro Race crankcase Derbi Euro 3, Euro 4</h2> <p>Metrakit now also offers a high-performance tuning crankcase for heavily tuned engines: the <strong>Metrakit Pro Race</strong>. Made from high-strength cast aluminium, it provides enhanced durability and performance-oriented technical features.</p> <p>It is based on the original Derbi Euro 3/4 design, perfect for tuners and racers aiming to unlock the full potential of their engine (up to 40 hp). The case can of course also be used for everyday riding.</p> <h3>Features Metrakit Pro race</h3> <p>The original Derbi engine cases are not designed for the extreme loads of tuned setups. Metrakit provides a remedy and offers a reinforced, optimized high-end upgrade that will satisfy even the most demanding tuners.</p> <ul> <li>Reinforced wall thickness for high loads</li> <li>More compact and lighter due to elimination of the starter motor</li> <li>More space for large-diameter carburetors</li> <li>Improved thermals / heat dissipation</li> <li>Compatible with crankshafts with enlarged crank webs</li> <li>Oversized needle bearing for the balancer shaft</li> <li>Oversized crankshaft bearings (6304)</li> <li>Prepared for Ø14 mm swingarm shaft (simple drilling required)</li> <li>Suitable for V-Force 3 and 4R reed valves</li> <li>Compatible with OEM Derbi Euro 3/4 parts</li> </ul> <p><strong>Note</strong>: Comes with central gasket and mounting hardware.</p>

METRAKIT

<p>This 74cc cylinder kit is an exact replica of the model used to break the world record at the Nardo test track. Made of high-quality cast iron, the cylinder features 5 transfer ports and a standard exhaust, a single-ring piston with a 49.5 mm diameter, and a one-piece high-compression cylinder head. The kit includes all necessary mounting components, such as gaskets and fixing parts. The performance of this cylinder is exceptional, reaching up to 15–16 HP with the right setup. Its torque is impressive, standing out especially in the high RPM range, as expected from a racing cylinder. Although very similar to the “Due Plus” model with modular head, this kit has been designed to set new performance standards and has been used to break records on the track. We recommend using a carburetor of at least 19 mm and a sport or racing exhaust to get the most out of this cylinder. It’s important to note that some users may notice two small holes under the intake port — these are required for proper cylinder lubrication and do not affect performance.</p>

TOP PERFORMANCES