The M18×1.5 O₂ sensor blanking bolt is an aftermarket sealing component for exhaust systems without an oxygen sensor or with an unused boss, for Honda Ruckus (4-stroke) models equipped with a GY6 engine. It is designed to neatly replace a missing oxygen sensor or to plug an M18×1.5 port intended for a sensor, thus preventing any exhaust leaks.
The M18×1.5 dimension is the standard thread pitch for oxygen sensors on many aftermarket muffler and exhaust manifold configurations. The blanking bolt screws into this thread and ensures a perfect mechanical seal, thanks to its precise design and the optional use of a suitable gasket/pin.
