Tag Archive for: DRT clutch sprocket PX

Clutch pinions from gear guru Denis Innocente (DRT) have just arrived from Italy. Denis specializes in special solutions and small series. Thanks to his enormous know-how, he is able to design and manufacture very interesting and special parts both in terms of quality and price. Its parts can now be found in almost every racing engine and confirm the high manufacturing quality of its special parts.

Here we present two clutch pinions from DRT, manufactured for use in the engines of the Vespa PX, Cosa, T5 and of course the older models such as the popular Rally or Sprint.
Thanks to the modular system that Vespa implemented very early on in its production, many parts are compatible with each other, even if there is a whole generation gap between the years of construction.

The 24 tooth pinion shown above fits the PX200 (up to approx. 1996), Rally200 and the early Cosa200 models (up to approx. 1991) without any modification. In these vehicles, the traditional, classic clutch type with 7 springs was installed (visually, by the way, immediately recognizable by the external spring plates). The PX200 models from 1996 and the Cosa from 1992 usually already use the Cosa2 coupling explained below.
These 200cc engines have a helical geared primary support in the ratio 23/65 ex works, which results in a gear ratio of 2,83. This means that a PX drives around 6000km / h at 100rpm.

For example, if such a motor is equipped with a Polini 210 Equipped with cylinders, it pulls out of the speed cell like a bull in the rut, but cannot fully convert its massive torque into more top speed. To do this, it cannot turn far enough like a Malossi 210, for example. In principle, it is then something like a powerful TDI diesel that is only driven in third gear on the motorway. The DRT pinion helps here in a very uncomplicated way. The DRT pinion has 24 teeth (instead of 23 as standard) and thus extends the primary reduction from 2,83 to 2,71. The whole thing works by simply exchanging the clutch pinion, the large primary gear with 65 teeth remains in the engine as it is. So the engine does not have to be opened for this gear ratio change!

If the motor has enough power to pull the longer reduction, it thanks it with a higher top speed or a lower speed level at the same speed.
The pinion only fits in conjunction with the original 65 tooth primary gear of the 200cc models. This in turn can of course also be used on almost all other ancillary shafts, such as the Der PX80 or PX125. Thus, for example, vehicles that are equipped with 8-inch tires but have been converted with a PX motor can easily be geared down for a sufficiently long time.

DRT also has a very interesting niche with a straight-toothed pinion type for the popular so-called COSA2 couplings occupied. The COSA2 coupling was used for the first time in the second series of the COSA models from around 1992. This type of coupling is characterized by very little manual force with very good controllability. It has a closed clutch basket (without holes for spring plates) and 8 springs inside. It is very popular in the tuning area because it uses stronger springs can transmit a very high torque and still remains easy to use. However, this type of clutch also has a completely different interior design, which means that it has not yet been possible to combine it with the well-known, longer reduction kits from Polini or Malossi. These have straight-toothed pinions, the Cosa is always helical-toothed in the original.

DRT has now filled this gap with straight-toothed pinions from its own production and also added two variants. We currently offer the DRT pinion with 22 teeth. This results in a gear ratio change from 2,78 (Polini 23/64) to 2,91 (22 / 64DRT / Polini), so much shorter.
This is useful for engines that have a high peak power in the upper speed range, but have a little less power in the lower speed range in order to always ensure a sufficiently fluid gear connection. So it is now finally possible to use a straight toothed primary in connection with a Cosa2 coupling. A possible application would be, for example, a high-speed 200cc Malossi engine.
A primary translation kit from Polini.

The parts will be in ours in the next few days One stop scooter shop online be available.

Impatient people are welcome to use
Email (info@scooter-center.com)
Telephone (02238-307430)
Fax (02238-307474)
order!