This is a genuine Zenoah replacement part. This is the cover for clutch side only. This covers the opening in the cylinder, allowing for access to the transfer port. You can see the flywheel side HERE. These will only fit Zenoah G320RC and G320PUM engines; and Fujiwara 40mm cylinder sets. These will not fit Zenoah G290RC and earlier engines, etc.

Zenoah part # 585727101