Carbhub Cylinder Assembly for STIHL 023/025 MS230/MS250 — 42.5mm Complete Rebuild Kit with Crankshaft & Spark Plug

High-quality Carbhub 42.5mm cylinder assembly kit engineered to replace worn engine parts on STIHL 023, 025, MS230 and MS250 chainsaws for a reliable rebuild.

If your STIHL saw is losing compression, smoking, or starting poorly, this complete 42.5mm cylinder assembly from Carbhub provides the core components needed to restore engine performance. The kit includes a precision-machined cylinder, piston, crankshaft and all accompanying seals, bearings, and fasteners so you can perform a full small-engine overhaul without sourcing multiple parts. Built to fit the common STIHL 023/025 and MS230/MS250 models, the parts are sized and packaged for straightforward replacement and reduced downtime.

What comes in the Carbhub 42.5mm cylinder assembly kit?

The kit supplies every major internals component required for a thorough cylinder and crankcase refresh. Components are matched for fit and timing to simplify installation and minimize compatibility issues.

• 1x precision cylinder body (42.5mm)
• 1x matching piston (42.5mm) with 2 piston rings and 2 clips
• 1x wrist pin and bearing cage
• 1x crankshaft with 2 crankshaft bearings and oil seals
• 1x spark plug and crankcase cover (engine pan) with 4 mounting bolts
• 1x extra crankcase connector included

How does this assembly improve saw performance?

Replacing worn cylinder components restores compression and reduces blow-by, which helps the engine burn fuel more efficiently and start more reliably. Fresh bearings and seals also eliminate common leak and play points, improving overall smoothness and reducing vibration.

• Restores cylinder compression for stronger throttle response
• New piston rings reduce oil consumption and smoke
• Replaced bearings and seals prevent leaks and looseness
• Included spark plug ensures proper ignition after rebuild

Is this assembly compatible with my STIHL model and how hard is installation?

The Carbhub kit is designed for STIHL 023, 025, MS230 and MS250 chainsaws that use a 42.5mm bore. Basic small-engine mechanical skills and the right tools are required; installation involves disassembly of the clutch, muffler, carburetor linkages and removal of the old cylinder, piston and crankshaft.

• Compatible with STIHL 023, 025, MS230, MS250 (42.5mm bore)
• Moderate difficulty—recommended for users comfortable with engine rebuilds
• Use torque specs, gaskets and proper timing during reassembly
• Professional installation suggested if unfamiliar with 2-stroke crankcase assembly

What should I check after installing the new cylinder assembly?

After assembly, verify compression, check for oil or fuel leaks, and confirm the engine idles and revs smoothly. A short break-in period under light load helps rings seat properly and ensures long-term reliability.

• Perform compression test to confirm restoration of pressure
• Inspect for leaks at seals, gaskets and crankcase connector
• Run at low RPM initially for ring seating, then test under load
• Re-torque bolts after warm-up if manufacturer recommends

Who is this for: This Carbhub 42.5mm cylinder assembly kit is ideal for homeowners, arborists and professional saw technicians who want a cost-effective way to revive a tired STIHL 023/025 or MS230/MS250. If your saw exhibits poor starting, reduced power, excessive smoke or oil leaks, and you can handle or arrange a mechanical rebuild, this all-in-one kit supplies the matched parts needed to get the saw back into dependable service.