The Vespa exhaust is of course always decisive for the famous sound of the old scooters. The smoke with a slightly oily smell, which is well-known among Vespa riders, also comes from the attachment.
In addition to these nostalgic and at the same time unmistakable features, however, the exhaust fulfils a much more important task. It mainly transports the exhaust gases out of the cylinder and at the same time dampens the sound produced by the exhaust gases. This is the only way to ensure that the scooter can deliver its full power to the road. Typical characteristics of a clogged exhaust are, in particular, poor acceleration behaviour and reduced top speed. These problems occur especially if the scooter is only used for short distances and the exhaust does not get properly hot.
Cleaning the exhaust: Various possibilities
One thing first: The reason for a clogged exhaust on two-stroke scooters is residues of burnt oil, which reduce the space in the muffler. This means that fewer exhaust gases can flow out.
Since the oil in the combustion chamber burns at temperatures below several hundred degrees, at least as high a temperature is required to loosen these residues. The only exception to this is the use of a wire brush, provided you can work with the brush in the exhaust. There are special, very thin brushes for this purpose that allow you to get inside the exhaust. This makes it relatively easy to remove the residue. However, this method is only suitable for light soiling.
A blowtorch is usually the better choice for larger amounts of dirt. To do this, the exhaust should first be removed and placed on a heat-resistant surface. It is also imperative that the work is carried out outdoors, as there is a risk of smoke poisoning indoors. With the help of the blowtorch, the exhaust should now be heated until it glows. Depending on the thickness of the material, this may take some time.
This loosens the stuck carbon particles and they can then be knocked out of the exhaust. In the case of particularly stubborn residues in the exhaust, oven cleaner can also be used to help. This should be put into the exhaust and then heated strongly. However, this produces a lot of smoke, some of which is harmful. The liquid with the cleaner should also be disposed of properly afterwards.
Burning out the exhaust – probably the best-known method
For many mechanics, the above-mentioned methods are probably less familiar than the following method of cleaning. The easiest way is to burn out the exhaust. To do this, you should logically stay outside again and make sure you have a fireproof surface. Petrol is now tipped into the exhaust, which is then distributed by carefully turning the exhaust. This liquid is then ignited. Extreme caution is required. In any case, sufficient distance should be kept and the ignition should best be carried out with the help of a Bunsen burner. This is the only way to guarantee that the distance is sufficient and that no burns occur due to flames or deflagrations.
Attention: With this variant, the local legal regulations must be observed! In some federal states, such actions are not allowed even on private property.
If necessary, this procedure can also be repeated. The flames burn off the residues and the exhaust can be used again without problems.
A question of economy: Cleaning or new purchase
Unlike many other new parts, it is often more worthwhile to buy a new exhaust system than to repair it, especially if the vehicle has a low mileage. Complete exhaust systems in OEM quality are often much cheaper, especially for small frames.
However, many Vespa riders also have the goal of keeping a Vespa completely in its original condition. In this case, it is not difficult to preserve the original part and continue to use it.
In any case, when removing the exhaust system, think about new gaskets for installation. Due to the high temperatures, the gaskets to the cylinder or to the manifold must always be replaced during installation.