Piaggio 478547 V-Belt Variator 736x18 – Vespa ET4 125 and Sfera 125

The Piaggio 478547 V-belt is the variator belt that transmits motion from the drive pulley to the driven pulley on early model Vespa ET4 125 and Piaggio Sfera 125 and Sfera RST 125 scooters. It is an original Piaggio spare part, measuring 736 x 18 mm, and occupies position 2 in the official "Drive Half-Pulley" table of the spare parts catalog. Product code 478547.

✓ Strengths

• Original catalog size – 736 mm in length and 18 mm in width: this is the geometry the variator expects, and it's crucial for acceleration and pick-up.
• Original spare part, not an adaptable one – this is the code Piaggio specifies in the catalog for these models.
• Toothed V-belt profile – the internal teeth make it flexible on the tight radii of the variator and limit overheating.
• Maintenance part – this is a wear-and-tear part: changing it in time prevents damage to pulleys and rollers, which cost much more.
• Stock still available – for vehicles out of production for years, finding the original belt in the correct size is the difficult part.

Technical features

Vehicle compatibility

List taken from the official Piaggio spare parts catalog (B2B).

Spare parts from the same table

If you open the crankcase to change the belt, these are the other codes from the official "Drive Half-Pulley" table. Contact us to check availability.

• 82523R – fixed drive half-pulley (position 3)
• 435027 – toothed bush (position 5)
• 436698 – spring washer (position 6) and 436789 – hexagonal nut (position 7)
• 434409 / 434410 – washers (positions 1 and 4)

Who it's perfect for

This is the right spare part for those who own a first series Vespa ET4 125 or a Sfera 125 and want to restore the transmission with the original part, not a generic equivalent. If the scooter has become slow to accelerate, "slips" uphill, or makes noise from the transmission compartment, the belt is the first thing to check — and it's also the cheapest to replace before wear affects pulleys and rollers.

Frequently asked questions

Is this belt suitable for my Vespa ET4 125?
It is suitable for the Vespa ET4 125 from the historical catalogs, which is the first series with the older engine, and it is the same belt as the Sfera 125 and Sfera RST 125. On subsequent ET4 models, Piaggio changed the engine and belt: if in doubt, send us your VIN and we will verify it.

How do I know if the belt needs changing?
Typical signs are a loss of initial acceleration, slipping uphill, a noise or whistle from the transmission compartment, and a lower top speed than usual. With the crankcase open, check for cracks on the teeth, frayed edges, and worn width. The exact replacement schedule is in your vehicle's owner's manual.

What is the difference between this and the 841213 belt?
The 841213 is the belt for more recent 125 and 150 4-stroke Piaggio Group models (Vespa LX, Liberty, Fly, X8, Runner, Atlantic). The 478547 is shorter and serves historical models: Sfera 125 and first series ET4 125. They are not interchangeable.

Is it an original spare part or an equivalent?
It is an original Piaggio spare part with manufacturer code 478547, the same that appears on the official exploded view diagram of the drive half-pulley. It is not a universal aftermarket belt.