Triumph and BSA are both British motorcycle manufacturers with a rich history, known for their parallel twin engines. The Bonnie (short for Bonneville) is a popular model from Triumph, while the Rocket III is a well-known model from Triumph and not BSA. It's important to note that BSA motorcycles, including their parallel twin models, were more prominent in the mid-20th century and are not as commonly produced today.
In terms of power and acceleration, it can vary depending on the specific model and year of production. However, Triumph motorcycles have generally been known for their performance-oriented characteristics, offering powerful engines and impressive acceleration. Triumph has continuously evolved their parallel twin engines over the years to deliver better performance, efficiency, and reliability.
BSA motorcycles, on the other hand, were more popular during the mid-20th century and their parallel twin engines were renowned for their smoothness and reliability rather than raw power. However, BSA also produced some high-performance models, such as the BSA A10 Rocket Gold Star, which had impressive power for its time.
It's worth mentioning that specifications and performance figures can vary significantly between different models, engine sizes, and years of production. To get accurate and up-to-date information on specific Triumph and BSA parallel twin models such as the Bonnie and Rocket III, it would be best to refer to official manufacturer websites, motorcycle magazines, or consult with authorized dealerships for the most recent details.