Outboard Cylinder Boring & Resleeving

For over 40 years now, Precision Cycle Inc has specialized in outboard cylinder boring, cylinder resleeving, honing, and piston fitting for 2-stroke and 4-stroke marine engines. From scored cylinder walls and seized pistons to worn sleeves and damaged outboard blocks, we machine cylinders to proper size, roundness, clearance, and finish so the engine can be rebuilt correctly.

Located in Orlando, Florida, we work with boat owners, marine repair shops, engine builders, and ship-in customers throughout the United States.

We machine many most new, late-model and vintage outboard cylinders blocks, including 2-stroke and 4-stroke marine engines that require boring, honing, sleeve removal, sleeve installation, and piston-to-wall clearance correction.

Outboard cylinders operate under high heat, load, and tight piston-to-wall clearances. When a piston seizes, rings break, or the engine overheats, the cylinder wall can become scored, tapered, out-of-round, or too worn to seal properly.

Outboard cylinder boring is usually needed after the cylinder wall has been damaged, worn, or distorted beyond what a simple hone can correct. Many customers first notice the problem as low compression, piston damage, scoring, or a loss of performance before they know the cylinder needs machining. Precision boring restores the cylinder to the correct size, shape, and piston clearance so the engine can be rebuilt properly instead of guessing at the repair.

• Most outboard cylinders are blind-hole bores.
• They require proper setup and specialized tooling.
• The bore must be straight, round, and properly finished.
• 2-stroke ports must be handled correctly.
• Poor boring can damage rings, reduce compression, or shorten engine life.

–Cylinder boring removes damaged material and sizes the cylinder for an oversized piston.
–Cylinder honing creates the final surface finish and crosshatch for ring seating.
–Cylinder resleeving replaces or installs a sleeve when the cylinder damage is too severe to clean up with boring alone.

1. Inspect cylinder damage.
2. Measure current bore size.
3. Determine whether boring or resleeving is needed.
4. Confirm piston size and clearance.
5. Set up the block/cylinder in the boring equipment.
6. Bore cylinder to the required size.
7. Hone to final finish.
8. Chamfer ports where needed on 2-stroke cylinders.
9. Final measure and clean.