tuning Gearbox
PRIMARY TRANSMISSION§ The primary transmission consists of a gearwheel for the countershaft and a toothed shaft that holds the driven pulley, the clutch and the clutch case. It makes sense to change the primary transmission if the driven pulley shaft is worn out or the thread is damaged. The gearbox cover bearing should be replaced as well. Don’t forget to order a new clutch nut and fresh gearbox oil. Primary Transmission
Model
Engine
Part No
POLINI, 15/38 teeth, GR*=2.53, +22,9%
for Vespa ET2 ´98-/LX/LXV/S 50cc
2T, AC
P2021405
€
MALOSSI, 16/37 teeth, GR=2.31, +30%
for Vespa ET2 ´98-/LX/LXV/S 50cc
2T, AC
M6711449
57,98
POLINI, 17/44 teeth, GR=2.59, +15%
for Vespa ET4/LX/LXV/S 125cm
4T, AC, Leader
P2021389
72,27
POLINI, 17/44 teeth, GR=2.59, +15%
for Vespa LX i.e./LXV i.e./S i.e. 125cc
4T, AC, Leader i.e.
P2021389
72,27
POLINI, 17/44 teeth, GR=2.59, +17%
for Vespa ET4/LX/LXV/S 150cc
4T, AC, Leader
P2021389
72,27
POLINI, 17/44 teeth, GR=2.59, +16%
for Vespa GT/GT L/GTS/GTV 125cc
4T, LC, Leader
P2021389
72,27
POLINI, 17/44 teeth, GR=2.59, +16%
for Vespa GT/GT L 200cc
4T, LC, Leader
P2021389
72,27
63,03
*GR = gear ratio
SECONDARY TRANSMISSION§ The secondary transmission consists of one part of the countershaft and the big gearwheel of the driveshaft. We consider it a little easier to change the secondary transmission compared to changing the primary transmission. Check the driveshaft bearing and change it if damaged or worn. Make sure to use a new splint for the rear wheel and fresh gearbox oil. Secondary Transmission
Model
Engine
Part No
MALOSSI, plugged, 14/47 teeth, GR*=3.36, +20%
for Vespa ET2 -´98 50cc
2T, AC
M678939
57,98
€
MALOSSI, grouted, 14/47 teeth, GR=3.36, +9%
for Vespa ET2 ´98- 50cc
2T, AC
M679968
57,98
MALOSSI, grouted, 14/47 teeth, GR=3.36, +11%
for Vespa ET2 ´99-/LX/LXV/S 50cc
2T, AC
M679968
57,98
MALOSSI, 15/47 teeth, GR=3.13, +17%
for Vespa ET4/LX/S 2V 50cc
4T, AC 2-valve
M6712144
61,34
MALOSSI, 15/47 teeth, GR=3.13, +25%
for Vespa LX 4V/S 4V 50cc
4T, AC 4-valve
M6712144
61,34
MALOSSI, plugged, 14/47 teeth, GR=3.36, +11%
for Vespa ET4 old 125cc -06/98
4T, AC
M678939
57,98
MALOSSI, grouted, 14/47 teeth, GR=3.36, +11%
for Vespa ET4 old 125cc 06/98-
4T, AC
M679968
57,98
MALOSSI, 16/42 teeth, GR=2.63, +7%
for Vespa ET4/LX/LXV/S 125cm
4T, AC, Leader
M6711860
57,98
MALOSSI, 16/42 teeth, GR=2.63, +7%
for Vespa LX 3V i.e./S 3V i.e. 125cc
4T, AC, Leader i.e. 3-valve
M6711860
57,98
MALOSSI, 16/42 teeth, GR=2.63, -2%
for Vespa ET4/LX/LXV/S 150cc
4T, AC, Leader
M6711860
57,98
MALOSSI, 16/42 teeth, GR=2.63, +25%
for Vespa GT/GT L/GTS/GTV 125cc
4T, LC, Leader
M6711860
57,98
MALOSSI, 17/49 teeth, GR=2.88, +10%
for Vespa GTS Super/GTS Super Sport 125cc
4T, LC, Quasar i.e.
M6712194
79,83
MALOSSI, 16/42 teeth, GR=2.63, +5%
for Vespa GT/GT L 200cc
4T, LC, Leader
M6711860
57,98
MALOSSI, 22/45 teeth, GR=2.05, +7%
for Vespa GTS/GTV 250cc
4T, LC, Quasar i.e.
M6714844
83,19
MALOSSI, 22/45 teeth, GR=2.05, +5%
for Vespa GTS/GTS Super/GTV 300cc
4T, LC, Quasar i.e.
M6714844
83,19
*GR = gear ratio
Technical Background Gearbox As the relation of primary to secondary transmission determines the amount of engine performance that is effectively used at the rear wheel, the gear ratio (GR) is essential to the setup of a gearbox. In order to change the gear ratio, it generally does not matter if the primary or the secondary transmission is modified. For race use it is common to change both components. The gear ratio is calculated by dividing the number of teeth of the big gearwheel by the number of teeth of the corresponding small gearwheel. The resulting ratio indicates, how „long“ or „short“ the primary or secondary transmission is. As a general rule: The smaller the ratio – the longer (and faster) the transmission.
< to the clutch
Primary Secondary
The following formula allows you to calculate, how much longer a tuning transmission is (in %), compared to the original one:
V= {1-( GR
GRsport orig
) }*100
ALL PRICES AS OF 05/2013, EXCL. VAT (NET), PLUS SHIPPING, SEE LAST PAGE www.sip-scootershop.com
to the rear wheel >
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