This Universal Parts Air Filter (SKU 151-294) is a cartridge-style replacement filter for long case 139QMB (QMB139) 50cc 4-stroke scooters, the Chinese GY6 50cc platform based on Honda's GY6 design. Long case engines are typically found on scooters with 12" wheels and a 729-length drive belt. A clogged filter robs power and hurts fuel economy, so swap it at every major service.
Check the engine code stamped on your engine case and confirm you have the long case (729 belt) before ordering. Short case engines with 10" wheels use a different filter. For the surest fit, compare your original filter's length and shape with the photos.
