Characteristics
The Nessi by Posch Performance is designed as a sporty touring exhaust with full everyday usability. The character of the exhaust system is aimed at excellent rideability and offers strong torque with a very nice power band. Very good pre-resonance behavior and a noticeable two-stroke kick at around 5000 rpm provide riding fun and confidence on the road.
RPM and port timings
Power peak: approx. 7500 rpm (depending on engine setup)
Recommended cylinder timings:
Exhaust timing: 190°
Transfer timing: 132°–134°
Blowdown timing: 28° to 29°
In practice, however, the Nessi also works well with significantly smaller timings, ranging from 128° to 186°.
Quality and sound
The exhaust systems from Posch Performance are manufactured in Germany to a very high standard from thick (1.5 mm) steel sheet. The high wall thickness of the material makes the Posch exhausts extremely robust. The unusually thick material also produces a deep and rich sound. We recommend the Scooter&Service rear silencer. The flange plate with the standard Ø54 mm bolt pattern also allows the use of silencers from PM-Tuning, MR-Parts, or MMW and similar. The outlet diameter of the silencer should be at least Ø25 mm. Posch exhausts are delivered oiled. Therefore, the exhaust should be treated with heat-resistant paint before the first ride.
Everyday usability
As one of the few exhausts in this performance class, the 'Nessi exhaust' fits with wide tires and center stand.
It was elaborately routed in a serpentine shape, which also gave it its name.
Fitment
The exhaust is welded in Germany on a specially made exhaust jig. This allows us to guarantee a very good fit. Please note that a Vespa engine may have some individual characteristics that can influence the fit. For example, the cylinder not being centered on the engine casing and the resulting possible rotation of the exhaust flange by several degrees can already decide whether an exhaust can be mounted easily.
Likewise, the Malossi engine casings are built more massively around the exhaust mount than original engine casings.
Versions
The exhaust system is available in two versions:
For Malossi Sport/MHR cylinders
For Quattrini M232/M244 cylinders
Conclusion
Beautiful resonance exhaust system, "Made in Germany" with high everyday usability and outstanding all-round performance