SERVICE Cylinder Bore, Hone, & Chamfer (Per Hole)

2 Stroke Broing! Service Includes:

• Cylinder Boring to restoration of roundness and straightness — eliminating the oval wear that new rings can’t overcome
• Precision honing to our specification using a rigid hone.
• Ideal 45° crosshatch finish for proper oil retention and fast, long-lasting ring seating in a marine environment.
• Critical port chamfering on every exhaust, transfer, boost, and intake port plus the top of the bore so rings glide smoothly without catching, chipping, or hanging up — vital for high-RPM two-stroke watercraft reliability.

The listed price is per hole, and when pistons are purchased from us.

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Why Your Watercraft Two-Stroke Needs This Service (Even If You’re Just Replacing Pistons & Rings)

Two-stroke PWC cylinders take a beating — high RPM, constant wide-open throttle runs, and the unique side-loading from the pump drive mean the bore quickly wears out-of-round (oval). The thrust faces wear faster than the sides, especially after high hours on the water. Once the cylinder is no longer perfectly round, even fresh rings can’t seal properly.

New pistons and rings alone will NOT fix it.

Rings are engineered to seat against a true round bore with the correct crosshatch. On an oval or lightly scored bore they flex unevenly, leave gaps, and never achieve a proper break-in. The result?

• Lost compression
• High blow-by into the crankcase
• Rapid ring and piston wear
• Excessive oil burning and blue smoke trailing behind you on the lake

Don’t waste money on new top-end parts if the bore isn’t restored to perfect roundness and surface finish first, if it is round, then there's no need to change anything!

How a Loose Top End & Excessive Blow-By Ruins Carb Tuning in Watercraft Two-Strokes

In a two-stroke PWC, the crankcase is the supercharger that pushes the fuel/air charge through the transfer ports into the cylinder. When the bore is oval, and rings don’t seal:

• Combustion gases blow past the rings, spiking crankcase pressure at the wrong moment.
• This disrupts the intake pulse that your carburetor (or carbs) rely on for accurate fuel delivery.
• Result: unstable vacuum signal, inconsistent jetting, and the classic two-stroke PWC nightmare — lean spots at WOT, rich bogging off idle, four-stroking, hesitation, and plugs that foul in a single ride.
• Oil mist gets forced into the combustion chamber and out the exhaust, creating heavy smoke and leaving you with a trail of blue haze on the water.

A worn bore turns a simple carb tune into an all-day frustration out on the lake. Hone the bore correctly and your jetting suddenly works the way the factory intended.