Cylinder Block 90cc

C90 Cast Iron Cylinder Block

For Moped, Cub, Dirt Bike & ATV

Fits Engines: 139FMB 147FMD 147FMF 150FMG

Material: High-Quality Cast Iron

This product is a C90 series cast iron cylinder block, designed for horizontal engines used in mopeds, Cub motorcycles, dirt bikes, and ATVs. It perfectly fits classic engine models such as 139FMB, 147FMD, 147FMF, and 150FMG. The cylinder block is manufactured from high-quality cast iron, offering excellent wear resistance, good thermal stability, and a long service life. The precision-machined cylinder bore provides an ideal running surface for the piston, ensuring stable compression ratio and reliable power output.

This cylinder block is primarily compatible with the following horizontal engine series:

• Quality Cast Iron Material: Made of high-quality gray cast iron or alloy cast iron, offering excellent wear resistance and resistance to thermal deformation for long service life.
• Precision Honed Bore: The cylinder bore is precision-honed to create a cross-hatch pattern for oil retention, aiding piston ring break-in and lubrication.
• OEM Mounting Dimensions: Manufactured strictly to original specifications, with cylinder height, bolt hole positions, etc., perfectly matching 139FMB and similar engines for direct replacement.
• Two Displacement Options: Available in 70/90cc and 110cc bore sizes to meet the repair needs of different engine displacements.

✅ Typical Symptoms of Cylinder Wear or Damage: Hard starting, significant power loss, burning oil (blue smoke from exhaust), low compression, unusual engine noises (knocking or pinging). If you experience these issues, the cylinder block may need inspection or replacement.

⚠️ Installation Note: When replacing the cylinder block, it is recommended to also replace the piston, piston rings, and cylinder head gasket. Clean the crankcase mating surface thoroughly before installation and tighten the cylinder head bolts to the specified torque and sequence as per the service manual. Cast iron cylinders are relatively heavy, so ensure proper support during installation. Allow proper engine break-in after installation.