Supertech Honda K 86.50mm Bore 1.181in Comp Height +11cc Dome 12:1 CR Pistons- Set of 4 (Excl Rings)

If you're rebuilding the heart of your Honda K-series engine and aiming for a significant bump in compression, this set of Supertech forged pistons is a solid choice. These pistons are designed to increase your engine's compression ratio to 12:1, which generally means more power and better throttle response when paired with appropriate tuning. The 86.50mm bore size is a common upgrade for K-series engines, and the +11cc dome volume is specifically calculated to achieve that 12:1 compression ratio with typical K-series cylinder heads.

Supertech is known for making well-built internal engine components, and these pistons are no exception. They are forged from high-strength aluminum alloy, which is much more durable and resistant to detonation than cast pistons, making them suitable for higher performance applications. The 1.181-inch compression height is a critical measurement that ensures proper piston-to-valve clearance and deck height when used with the correct connecting rods. Remember that these pistons are sold as a set of four and do not include piston rings, so you'll need to source those separately to complete the installation.

When installing these pistons, it's crucial to ensure your engine block is bored and honed to the exact 86.50mm size specified. Proper ring gap, bearing clearances, and assembly lubrication are also essential for the longevity of your engine build. Given the increased compression ratio, you'll likely need to adjust your engine's fuel and ignition timing through ECU tuning to take full advantage of these pistons and prevent issues like pre-ignition or knocking.