SINCRO/SINCRO REPLICA/NURBURG/MATRIX input shaft assemblies: THE racing gear box components. A shorter 3rd and 4th gear but is only possible in combination with the PARMA cog with 47 teeth, which allows even finer gear ratio tuning to the rest of the gear box. The SYNCRO PISTA version also has a shorter 2nd gear. It is advisable to begin with the NURBURG gear cog an then to progressively shorten the individual ratios according to the power characteristics of your motor. The NURBURG/ SINCRO/ MATRIX input shaft assemblies all require the PARMA cog with 47 teeth.
The SINCRO REPLICA and NURBURG input shafts shorten the 4th gear ratio even more than the RUNNER version. The 3rd gear ratio is also shorter. The ROVIGO 1st gear cog with 55 teeth and the 2nd gear cog with 55 teeth, both produced by DRT, have proved very successful in combination with these shaft assemblies.
The SINCRO PISTA shaft assembly has also a shorter 2nd gear ratio. These input shaft assemblies with 19, 17, 13 and 10 cog teeth respectively are conceived for use on the race track. In performance orientated motor projects the use of the output shaft gear cogs, produced by DRT, with 54 and 51 teeth for the 1st and 2nd gears and a cog with either 49 or 50 teeth on the 3rd gear cog has proved successful.
Currently the MATRIX input shaft assembly conversion kit rules the roost of race series gear box tuning. Denis Innocente: "It won in all classes and races, where it was used in 2011". A rider with a scooter equipped with a PARMA kit performance racing cylinder combined with a 19mm carb rode over the finish line with an end-speed of 140 km/h (88 mph). In high end motor tuning projects this input shaft has proved best in combination with the output shaft gear cogs with a PARMA 4th gear, a 1st gear with either 55 or 54 teeth, 51 teeth on the 2nd gear cog and the 3rd gear cog with either 49 teeth, also produced by DRT, or the OE PIAGGIO item for the 3rd gear with 50 teeth.
The above listed gear ratio combinations are of course only recommendations for use on kart tracks, smaller race track circuits and street use. For larger circuits such as Cadwell park or the Nürburgring in Germany a taller gear ratio setup is necessary.
Conclusion: If you race or intend to you will not be able to do without these gear box conversion kits.