Teil eines Tachometers einer Vespa

Dethrottling a Vespa

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Many Vespa riders are not satisfied with the speed of their motorised two-wheeler. They wish they could get from A to B faster. Often their vehicles are simply throttled. So how do the owners manage to get from A to B faster? In other words, the question is how it is possible to de-throttle a Vespa.

When the spark doesn’t fly

It is a kind of tuning. The ignition prevents the spark from jumping over from a certain speed or when a certain rpm is reached. The Vespa could therefore theoretically reach higher speeds. However, the high-voltage capacitor ignition throttles the two-wheeler.

Higher speed

It is possible to disconnect this ignition. This can be replaced by an open ignition, for example. In this way, riders can achieve higher speeds.
However, there is a problem. If the throttle is removed, riders are no longer allowed to ride the Vespa with an A 1 or AM driving licence.

Possibilities to throttle the Vespa

If you remove the distance ring between variator and belt pulley, you change the distance between variator and V-belt. This makes the Vespa go faster.

Removing the throttle pulley

Specialists unthrottle a Vespa by removing the throttle valve stop positioned on the carburettor. Once the throttle is removed, it is possible to turn the throttle grip completely. The throttle slide stop restricts the turning of the grip. This means that riders cannot give full throttle.

Dethrottling by tuning the air filter

A throttled air filter sucks in less air. If you remove the air filter and loosen the screws, you expose the throttle. If owners of a Vespa replace the air filter with a different filter, the performance of the two-wheeler is usually optimised. Because of the changed filter, the carburettor must be readjusted.

Dethrottling by machining the intake manifold

Another option to de-throttle the Vespa is to work on the intake manifold. It throttles the power of a Vespa. By milling out or replacing the intake manifold, the latter can be extended.

Throttle the exhaust

Experts throttle the exhaust by removing the cone. Another method is to weld the dummy pipe to the engine. In this way, it is possible to increase the power of the Vespa somewhat. A final variant for removing the throttle is to open the narrowed rear silencer.

Dark Vespa workshop, with a Vespa in the centre with the light shining on it

Legal regulations

Structural changes to the air filter, exhaust or carburettor have consequences. Drivers of the Vespa are no longer allowed to steer it without further ado. There is a risk of a fine of 50€. There is also the risk of losing insurance cover. If unthrottling means a danger to people and the environment, the fine is 90€. In addition, there may be a point in Flensburg.

Legal or illegal?

Dethrottling is legal as long as DEKRA, TÜV or a similar recognised test centre approves the modifications made. After the structural changes have been officially noted in the vehicle documents, driving the tuned Vespa is legal.

What you have to pay attention to

If the Vespa is significantly faster after the modifications have been made or if the engine capacity is larger, the driving licence of class A or AM is no longer sufficient. Rather, riders then require class A2. If the corresponding driving licence is not available, this is not merely an administrative offence. If the owner of the vehicle does not present the required papers, this is to be regarded as a criminal offence. This may result in a fine or even imprisonment.

Test centres and professionals

If you make changes to your Vespa, you are only within the legal limits if you register the tuning with the TÜV. Only then do they have official permission to drive the dethrottled bike. It is advisable to make an appointment with the TÜV or DEKRA before throttling your vehicle. To be sure that the modifications to their own Vespa are legal, responsible two-wheeler owners should consult professionals. Only experienced mechanics can successfully modify a Vespa.


Without experience and expert knowledge, the removal of a throttle can be complicated or even lead to damage to the vehicle. If the Vespa has been throttled, TÜV or DEKRA will issue an inspection report. If it is positive, owners receive a test certificate. With this, they apply for the modified entry in the registration certificate at the registration authority.

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