No, a bigger rear sprocket does not make a motorcycle go faster. In fact, it has the opposite effect.
The sprockets in a motorcycle's chain drive system determine the gear ratio between the engine and the rear wheel. A larger rear sprocket means that for each revolution of the engine's output shaft, the rear wheel will rotate fewer times. This increases the torque at the rear wheel but reduces the top speed.
On the other hand, a smaller rear sprocket will result in the rear wheel rotating more times for each revolution of the engine. This reduces torque at the rear wheel but increases the top speed.
So, if you want to increase the acceleration and low-end power of a motorcycle, you can opt for a larger rear sprocket. However, this will sacrifice some top speed. Conversely, if you desire higher top speed, a smaller rear sprocket would be more suitable.
It's important to note that changing sprocket sizes can also affect the motorcycle's overall performance, including fuel efficiency, gear ratios, and the engine's operating characteristics. Therefore, it's advisable to consult with an experienced mechanic or motorcycle specialist who can provide guidance based on your specific requirements and the motorcycle's specifications.