57Φ bore up & big valve cylinder head kit (148cc) for Hi Speed CT125 (JA55) and other old horizontal engines (excluding tax and shipping included)

Big valve cylinder head for Honda's old horizontal engine. Intake 28Φ, exhaust 24Φ. Please note that this product cannot be installed on genuine cylinders. Compatible with cylinder inner diameter 56Φ or more.
By using a big valve, efficiency during intake and exhaust will be dramatically improved. Furthermore, the port has been enlarged for a pleasant engine feeling.
A set includes a high cam and reinforced valve spring.

This is a bore up kit for Honda's old horizontal engine. Although there are products from other companies with larger displacements on the market, we have concluded that the cylinder bore of 57mm has the best balance in terms of engine durability and extension in the high rotation range. After installing this product, it has been used for more than 10,000km without any trouble even under harsh usage conditions. This is a masterpiece that we can recommend with confidence.
*When installing this product for public road use, you will need to apply for changes to your license, insurance, taxes, etc. Please deal with these matters yourself.