Piaggio Original Flywheel Magnet Fan 50 2T – OEM 828765

The original Piaggio 828765 fan is the impeller bolted onto the flywheel magnet of 50cc two-stroke air-cooled engines. It rotates with the crankshaft and pushes air into the shroud: on air-cooled models, it is the only component that cools the cylinder and cylinder head fins. Product code 828765.

Strengths

• Original Piaggio Group spare part, the same one fitted at the factory on Vespa, Piaggio, Aprilia, Gilera, and Scarabeo vehicles.
• Blade geometry calibrated to the engine: the airflow is exactly what the shroud was designed for.
• Correct mass distribution: the impeller is screwed onto the flywheel magnet, and its balancing is part of the engine design.
• Three metal bushings embedded in the plastic, so the screws do not crush the body and the seal remains secure over time.
• Can be replaced without removing the flywheel or touching the ignition: simply remove the shroud cover.
• A versatile spare part: it appears in thirty-nine official catalogs, from the Zip to the Vespa Sprint.

Technical specifications

Vehicle compatibility

List transcribed from the official Piaggio Group spare parts catalog (B2B area). Items indicated as "historical catalogs" correspond to the 1998-2005 window of vintage catalogs: for those models, the exact year of production is not declared.

Who is it perfect for

It is for those who hear a rubbing noise or a ticking sound from the flywheel area, for those who notice a vibration that increases with engine speed — a sign that a blade is missing and the rotating mass is unbalanced — and for those who find that the engine loses its responsiveness when hot. It is also the right part to replace preventively when the crankcase is opened for other work and the impeller plastic is years old and has undergone many thermal cycles.

Frequently asked questions

How many do I need?
Only one per vehicle. The Piaggio catalog specifies a quantity of one for all models where this code appears, because the impeller is unique and is bolted to the flywheel magnet. If you are rebuilding the engine, consider also replacing the three screws and three wavy washers, which cost very little.

My catalog lists 487796: is it the same part?
That code is indicated as the previous reference for the same fan, but it no longer appears in current spare parts catalogs, where the position is occupied by 828765. If your manual cites 487796, this is the spare part that now replaces it. In case of doubt, write us your chassis number and we will verify.

How do I know if it needs to be replaced?
There are three signs. A rubbing or plastic-on-plastic noise from the flywheel area; a vibration that increases with RPMs, typical of a broken blade unbalancing the rotating mass; the engine losing its responsiveness and overheating when at operating temperature. Once the shroud is removed, cracks are visible to the naked eye.

What happens if I leave it broken?
On an air-cooled two-stroke, there is no workaround: without forced airflow, the cylinder reaches critical temperatures within just a few kilometers. Classic damage includes piston seizure and scoring of the cylinder barrel, which costs many times more than the price of the fan. This is not a failure that should be delayed.

Is replacement complicated?
No. Remove the side fairing to access the shroud cover, unscrew the three M5 screws, slide the impeller off the hub, and mount the new one, making sure to include the wavy washers. You do not need to remove the flywheel, and you do not need to touch the ignition. It takes a leisurely hour, much less in a professional workshop.

Is it a genuine spare part?
Yes, it is an original Piaggio Group spare part, factory code 828765, the one listed in the Flywheel magneto diagram of the official catalogues. Moon Bike S.r.l. is an official Piaggio Group retailer based in Cercola, in the province of Naples, and deals exclusively in genuine spare parts with the manufacturer's warranty.