Hyceker MS291/MS271 Cylinder Piston Kit – 47mm Big Bore Top End for Stihl MS 291/MS 271 Chainsaws

Hyceker MS291 and MS271 Cylinder Piston Kit — 47mm Big Bore Top End for Stihl Chainsaws

Give aging Stihl MS291 and MS271 models new life with Hyceker's 47mm big bore cylinder kit. This top end upgrade is designed to improve airflow and compression in the engine’s upper section, potentially delivering a more responsive feel during demanding cuts. The kit is built for a round intake with a clamp style connection, a detail that matters when pairing with select Stihl models and after confirming your intake configuration.

Compatibility, design, and what’s included

The round intake variant is intended for clamp style round intake installations and is compatible with Stihl MS291 and MS291C as well as MS271 and MS271C Farm Boss variants. The 47mm bore marks a true big bore upgrade that may enhance midrange torque and throttle response on supported engines. This version explicitly uses a round intake connection, so please verify your system before purchase.

• Fits Stihl MS291 and MS291C gasoline chainsaws for top engine rebuilds
• 47mm big bore top end for Stihl MS271 and MS271C Farm Boss models
• Round intake clamp style design; verify your intake style before purchase
• Replacement part references: 1141-020-1206 for cylinder kit; 9523-003-4304 bearings; 9639-003-1585 seals
• Package includes: 1 x cylinder and piston kit, 2 x crankshaft ball bearings, 2 x crankshaft oil seals, 1 x piston needle bearing, 1 x spark plug, 1 x E-clip

Real-world use and benefits to consider

In practice, a 47mm bore can influence how the top end breathes, which may translate to crisper throttle response during heavy cutting, longer sessions, or when you push the saw into tougher tasks. The included crankshaft bearings and seals are intended to support smoother rotation and reliable operation between maintenance intervals. While results vary by setup and usage, this kit aims to offer a practical upgrade path without altering the rest of the machine.

• Potential for more responsive power during demanding cuts
• Includes essential wear parts to support ongoing operation
• Designed for clamp style round intake to match select Stihl engines
• Comprehensive replacement kit reduces the need for separate purchases

Installation and care tips

Before installing, confirm your model’s intake style and bore size. Follow standard safety practices and torque specs when reassembling the top end. Use fresh gaskets and proper lubrication during installation to help optimize performance and longevity.