CVT (Continuously Variable Transmission) powertrain efficiency generally ranges from 50% to 80%, creating opportunities to improve power transfer through optimization of the primary pulley geometry. This study investigates the effect of Drive Pulley inclination angle variations on the torque and power characteristics of a Mio Z 125 CC motorcycle across different engine speeds. A quantitative experimental method was employed using four Drive Pulley configurations: 14° (standard), 13.6°, 13°, and 12.5°. The 14° configuration produced a maximum torque of 11.73 Nm at 3,878 RPM and power of 7.36 HP at 7,292 RPM. The 13.6° configuration generated 13.24 Nm at 3,387 RPM and 7.79 HP at 6,848 RPM, while the 13° configuration produced 13.56 Nm at 3,350 RPM and 7.81 HP at 6,250 RPM. The 12.5° configuration achieved the highest torque and power, reaching 15.99 Nm at 3,250 RPM and 7.91 HP at 3,906 RPM. The increased performance is associated with earlier V-Belt engagement and faster expansion of the effective primary pulley diameter. These findings indicate that reducing the Drive Pulley inclination angle can strengthen low-speed torque and modify the power delivery characteristics of the CVT system.
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