Piaggio Original Water Pump Oil Seal – OEM 82991R

The original Piaggio 82991R water pump oil seal is the sealing ring that isolates the water pump shaft inside the flywheel cover. It is the original equipment replacement part for liquid-cooled engines in the group — Piaggio, Vespa, Aprilia, Gilera, and Moto Guzzi. You need one per vehicle. Product code 82991R.

✓ Strengths

• Original Piaggio Group spare part – code 82991R, the same one fitted at the factory
• The part that separates water and oil – if it fails, coolant leaks into the engine crankcase
• A single reference for the entire group – from 125cc scooters to Aprilia 660 twin-cylinders and the Moto Guzzi V100
• Aprilia reference AP8590055 – a single unified code following catalog consolidation
• Change it with the bearing – open the flywheel cover only once and redo the seal completely

Technical features

Vehicle compatibility

This list is taken from the official Piaggio Group spare parts catalog (B2B area) and verified against the group's spare parts catalogs: the part number appears in 125 different catalogs, always with a quantity of 1. The years indicated are those for which the spare part is provided for that model. Before ordering, verify part number 82991R in your vehicle's catalog.

Who it is perfect for

This oil seal is for anyone rebuilding the water pump of a Piaggio Group vehicle — Beverly, MP3, X8, X9, X10, X Evo, Vespa GTS and GTV, Aprilia Atlantic Sport City Scarabeo RS 660 Tuono Tuareg Shiver Dorsoduro, Gilera Nexus Fuoco GP 800, Moto Guzzi V100 and Stelvio. It costs a few euros and is exactly the part that determines whether the coolant stays where it belongs or ends up in the oil.

Frequently asked questions

How many do I need for my vehicle?
Just one. The Piaggio catalog specifies a quantity of one for all models where this part number appears, because the water pump shaft has only one seal on that side. The 82755R bearing from the same diagram is different, as two are required per vehicle.

Where is it exactly?
Inside the flywheel/magneto cover, the side cover of the engine. On these engines, the water pump is integrated into the cover and driven by the crankshaft: the oil seal isolates the impeller shaft from the oil side. On the twin-cylinder Aprilia motorcycles, it is in the diagram dedicated to the water pump.

My catalog shows 842595: is it the same part?
Yes. In the catalog, 842595 and 82991R are two references for the same seal, and retailers treat them as a single item. If your workshop manual or mechanic indicates 842595, this is the correct spare part to order. The same applies to the Aprilia reference AP8590055.

How do I know if it needs to be changed?
The classic sign is the coolant level dropping without visible leaks, accompanied by milky or foamy engine oil on the dipstick. Another clue is dripping from the weep hole under the flywheel cover. In both cases, the seal must be replaced immediately.

Should I also change the bearings and impeller?
It is strongly recommended. To reach the oil seal, you have to open the flywheel cover anyway, so you might as well rebuild the entire pump: bearings, seals, and the impeller cost little, and reinstalling old ones means risking having to reopen everything after just a few months. If you need them, write to us and we will bundle them for you.

Is it an original spare part?
Yes, it is the original Piaggio Group spare part, factory code 82991R, the same one that Aprilia identified as AP8590055. Moon Bike S.r.l. is an official Piaggio Group retailer based in Cercola, in the province of Naples, and deals exclusively in original spare parts covered by the manufacturer's warranty.