This is the Malossi Torque Driver that works with many Minarelli based scooter and others. Of a more detailed but not comprehensive list see below.

NOTE: The Malossi Torque Driver is available in either a 33mm or 34mm internal diameter. It is your responsibility to determine which one your specific scooter needs.The scooters below are those listed by Malossi, all have the disclaimer of either a 33 or 34mm. This is due to the fact this is a performance part and is designed to work with other aftermarket parts that might use a different size than stock.

Description
The mobile driven split pulley comes from our racing department's many years of experience, and is manufactured with the best possible special nitrided steels in order to ensure a long life.
This component called Torque Driver for its specific function of determining the exact shifting moment, was calculated to give the vehicle the maximum possible acceleration in connection with the specific power of any single engine. The spiral's peculiar shape was studied to fix the RPMs on the point of maximum power.
It was expressly created to complete the development of boosted motors withour cylinders, variators and the special Malossi Kevlar Belts, allowing to fully exploit your vehicle's notable torque and power.
The new Malossi mobile driven split pulley ensures, on boosted vehicles,extraordinary acceleration and an extremely progressive and fluid torque output to the wheel. The tracks on the Malossi mobile driven split pulley were studied and designed on CAD-CAM systems and machined on CNC machinetools in order to guarantee total interchangeability with the original component and extremely high machining accuracy.
This new Malossi product is a concentrate of today's state-of-the-art technology.

This Part Works With:

NOTE:We would like to clear up issues with which version scooters use stock so we can help others. If you know what size your specific scooter uses please email us and let us know so we can update this parts list with accurate info.

APRILIA
AMICO 50 2T - Depends on year
AREA 51 50 2T LC - Uses the 34mm
GULLIVER 50 2T - Depends on year
GULLIVER 50 2T LC - Depends on year
RALLY 50 2T (MINARELLI) - Depends on year
RALLY 50 2T LC (MINARELLI) - Depends on year
SCARABEO 100 2T - Uses the 33mm
SCARABEO 50 2T - Depends on year
SONIC 50 2T - Uses the 34mm
SONIC 50 2T LC - Uses the 34mm
SR 50 2T <-1993 - Uses the 33mm
SR 50 2T 1994-> - Depends on year
SR NETSCAPER 50 2T LC (MINARELLI) - Uses the 34mm
SR RACING 50 2T LC (MINARELLI) - Uses the 34mm
SR REPLICA 50 2T LC - Depends on year
SR STEALTH 50 2T LC (MINARELLI) - Uses the 34mm
SR WWW 50 2T - Uses the 34mm

ATALA
CAROSELLO 50 2T - Depends on year

BENELLI
491 GT 50 2T (MINARELLI) - Depends on year
491 SPORT 50 2T LC (MINARELLI) - Depends on year
K2 100 2T - Uses the 33mm
K2 50 2T - Depends on year
K2 50 2T LC - Depends on year
NAKED 50 2T - Depends on year
PEPE 50 2T - Depends on year
PEPE LX 50 2T euro 2 (QJ1E40QMB-4) - Uses the 33mm
QuattronoveX 50 2T euro 2 - Uses the 33m

BETA
ARK 50 2T - Depends on year
ARK 50 2T LC - Depends on year
CHRONO 50 2T - Depends on year
EIKON 50 2T LC - Uses the 34mm
QUADRA 50 2T - Uses the 33mm
TEMPO 50 2T - Uses the 33mm

CPI
ARAGON GP 50 2T - Uses the 33mm
HUSSAR 50 2T <-2002 (50 C) - Uses the 33mm
HUSSAR 50 2T 2003-> - Uses the 33mm
OLIVER 50 2T <-2002 (50 C) - Uses the 33mm
OLIVER 50 2T 2003-> - Uses the 33mm
POPCORN 50 2T <-2002 (50 C) - Uses the 33mm
POPCORN 50 2T 2003-> - Uses the 33mm

DINLI
T.REX 50 2T - Uses the 33mm

E-TON
VIPER RXL 50 2T - Uses the 33mm
VIPER RXL 90 2T - Uses the 33mm

EXPLORER
CRACKER 50 2T 2003-> (GE 1E 400 MB) - Uses the 33mm

FANTIC
BIG WHEEL 50 2T - Uses the 33mm

GARELLI
GSP 50 2T LC euro 2 (1PE40MB) - Depends on year
PONY 50 2T - Uses the 33mm
SR 50 2T - Uses the 33mm
TIESSE 50R 50 2T euro 2 (1E40QMB) - Uses the 33mm

HUPPER
MONTECARLO 30 50 2T (1E40QMB) - Uses the 33mm

ITALJET
BAZOOKA 50 2T - Uses the 33mm
DRAGSTER 50 2T LC - Uses the 34mm
MILLENNIUM 100 2T - Uses the 33mm
PISTA 2 50 2T - Uses the 33mm
PISTA 50 2T - Uses the 33mm
REPORTER 50 - Uses the 33mm
SCOOP 50 2T - Uses the 33mm
YANKEE 50 2T - Uses the 33mm

KEEWAY
F-ACT 50 2T - Uses the 33mm
GOCCIA 50 2T (KW1E40QMB-4 ) - Uses the 33mm
HURRICANE 50 2T euro 2 (KW1E40QMB) - Uses the 33mm
MATRIX 50 2T (KW1E40QMB-4) - Uses the 33mm
PIXEL 50 2T euro 2 (KW1E40QMB ) - Uses the 33mm
RY8 50 2T (KW1E40QMB-4 ) - Uses the 33mm

LAVERDA
QUASAR 50 2T (AR 03) - Uses the 33mm

LEM
FLASH 50 - Uses the 33mm
GHIBLI 50 - Uses the 33mm
TORNADO 50 - Uses the 33mm

MALAGUTI
CENTRO 50 2T - Depends on year
CIAK 50 2T - Depends on year
F10 50 2T - Depends on year
F10 WAP 50 2T euro 2 (QJ*CMA03C*) - Uses the 33mm
F12 - PHANTOM 50 2T - Depends on year
F12 - PHANTOM 50 2T LC - Depends on year
F12 DIGIT KAT - PHANTOM 50 2T LC - Depends on year
F12 R ARIA 50 2T euro 2 (QJ*CMA02C*) - Uses the 33mm
F12 R LC 50 2T LC euro 2 - Depends on year
F15 FIREFOX 50 2T LC - Depends on year
YESTERDAY 50 2T - Depends on year

MBK
ACTIVE 50 - Depends on year
BOOSTER 100 2T - Uses the 33mm
BOOSTER 50 2T euro 0-1 - Depends on year
BOOSTER NG 50 2T euro 0-1 - Depends on year
BOOSTER ROCKET 50 2T euro 0-1 - Depends on year
BOOSTER SPIRIT 50 2T euro 0-1 - Depends on year
BOOSTER X 50 ie 4T LC euro 2 - Uses the 34mm
EVOLIS 50 2T - Depends on year
FIZZ 50 2T - Depends on year
FLIPPER 50 2T - Depends on year
FORTE 50 2T - Depends on year
HOT CHAMP 50 2T - Depends on year
MACH G 50 2T - Depends on year
MACH G 50 2T LC - Depends on year
NITRO 100 2T - Uses the 33mm
NITRO 50 2T LC - Depends on year
OVETTO 100 2T - Uses the 33mm
OVETTO 50 2T - Depends on year
SORRISO 50 2T <-1995 - Uses the 33mm
SORRISO 50 2T 1996-> - Depends on year
STUNT 50 2T euro 0-1 - Depends on year
TARGET 50 2T - Uses the 33mm

MOTRON
SYNCRO 50 - Uses the 33mm
THUNDER'S 50 - Uses the 33mm

YAMAHA
AEROX 100 2T - Uses the 33mm
AEROX 50 2T LC euro 0-1 - Depends on year
AEROX 50 2T LC euro 2 - Depends on year
AXIS 50 2T - Uses the 33mm
BELUGA 50 - Uses the 33mm
BREEZE 50 2T - Depends on year
BW'S 100 2T - Uses the 33mm
BW'S 50 2T euro 0-1 - Depends on year
BW'S NG 50 2T euro 0-1 - Depends on year
CRZ 50 2T - Uses the 33mm
CT 50 2T - Uses the 33mm
GIGGLE 50 ie 4T LC euro 2 (A311E) - Uses the 34mm
JOG 50 2T - Depends on year
JOG ER 50 2T - Depends on year
JOG R 50 2T - Depends on year
JOG Z 50 2T - Depends on year
JOGRR 50 2T LC euro 2 - Depends on year
NEO'S 100 2T - Uses the 33mm
NEO'S 50 2T - Depends on year
NEO'S 50 ie 4T LC euro 2 (A316E) - Uses the 34mm
SLIDER 50 2T - Depends on year
SPY 50 2T - Depends on year
VINO 50 2T - Depends on year
VOX 50 ie 4T LC - Uses the 34mm
WHY 50 2T - Depends on year
ZEST 50 2T - Depends on year
ZUMA 50 2T - Depends on year (YW50 Zuma use 33mm)