Methods and systems are provided for coatings of a portion of an engine block shaping a combustion chamber. In one example, the engine block includes a first coating with a thermal conductivity higher than a conductivity of the engine block arranged in an upper region of the combustion chamber and a second coating with a thermal conductivity lower than the conductivity of the engine block arranged in a lower region of the combustion chamber, and where the second coating touches the first coating.

Provided is a cylinder liner having a first portion with a first thermal conductivity and a second portion with a second thermal conductivity. The first portion having the first thermal conductivity can include as-cast projections or a coating of a material, as desired. The first thermal conductivity can be greater than the second thermal conductivity. In this manner, the cylinder liner can exhibit a thermal conductivity gradient.

Provided is a cylinder liner having a first portion with a first thermal conductivity and a second portion with a second thermal conductivity. The first portion having the first thermal conductivity can include as-cast projections or a coating of a material, as desired. The first thermal conductivity can be greater than the second thermal conductivity. In this manner, the cylinder liner can exhibit a thermal conductivity gradient.

Provided is a cylinder liner having a first portion with a first thermal conductivity and a second portion with a second thermal conductivity. The first portion having the first thermal conductivity can include as-cast projections or a coating of a material, as desired. The first thermal conductivity can be greater than the second thermal conductivity. In this manner, the cylinder liner can exhibit a thermal conductivity gradient.

Provided is a cylinder liner having a first portion with a first thermal conductivity and a second portion with a second thermal conductivity. The first portion having the first thermal conductivity can include as-cast projections or a coating of a material, as desired. The first thermal conductivity can be greater than the second thermal conductivity. In this manner, the cylinder liner can exhibit a thermal conductivity gradient.

Methods and systems are provided for coatings of a portion of an engine block shaping a combustion chamber. In one example, the engine block includes a first coating with a thermal conductivity higher than a conductivity of the engine block arranged in an upper region of the combustion chamber and a second coating with a thermal conductivity lower than the conductivity of the engine block arranged in a lower region of the combustion chamber, and where the second coating touches the first coating.

A method of retrofitting a V-twin engine for increasing displacement. A cylinder replacement is performed by dismounting each of a pair of original cylinders from a crankcase. A pair of replacement cylinders are provided, each having a second cylinder bore diameter larger than a first cylinder bore diameter of the original cylinder to provide the V-twin engine with a second displacement greater than a first displacement of the original cylinder. A replacement spigot portion from each of the pair of replacement cylinders are aligned with a respective bore of the crankcase. The replacement spigot portion includes a second outer diameter larger than a first outer diameter of an original spigot portion. The second outer diameter of the replacement spigot portion and the crankcase bore diameter defining a subsequent diametric clearance smaller than an original diametric clearance of the original cylinders.

A cylinder for a V-twin engine includes a section of steel tubing cut to a length. The section of steel tubing includes a first portion having a first wall thickness and a second portion having a second wall thickness less than the first wall thickness. The second wall thickness is less than 0.050 inch. The section of steel tubing includes a first ribbing pattern on an outer surface, within the first portion, and a second ribbing pattern including multiple ribs formed on individual ribs of the first ribbing pattern. A cast body is provided on the first portion of the section of steel tubing so that the section of steel tubing is fixedly secured within the body to form a cylinder sleeve defining a cylinder bore. The second portion having the second wall thickness extends from an end of the body to be received within a bore of a crankcase.

In an ignition device having high voltage wiring, the ignition device which prevents and/or suppresses the occurrence of serious damage due to an electric shock is provided. In the ignition device which includes: an ignition plug that generates a plasma discharge; a DC/AC conversion device that outputs AC power toward the ignition plug; a DC power supply device which is arranged in a different package from that of the DC/AC conversion device and outputs DC power to the DC/AC conversion device via wiring; and a power circuit breaker that conducts and/or interrupts the output of said DC power supply device, the power circuit breaker interrupts the output of the DC power supply device at least once between ignition operation and ignition operation.

Provided is a cylinder liner having a first portion with a first thermal conductivity and a second portion with a second thermal conductivity. The first portion having the first thermal conductivity can include as-cast projections or a coating of a material, as desired. The first thermal conductivity can be greater than the second thermal conductivity. In this manner, the cylinder liner can exhibit a thermal conductivity gradient.