The performance of a motorcycle engine is influenced by various factors, including the design, displacement, tuning, and technology used. Each engine configuration you mentioned has its own characteristics and advantages. Let's discuss them briefly:
Inline V: While Moto Guzzi Le Mans features a V-twin engine, it's not an inline V configuration. An inline V configuration is relatively uncommon in motorcycles, and examples of such engines are rare. It's difficult to make a generalized statement about the performance of inline V engines since they vary depending on specific design and tuning choices.
Transverse V: Harley-Davidson motorcycles typically feature a V-twin engine with a transverse configuration. Transverse V engines offer a low center of gravity and a broad power delivery. They often prioritize torque rather than high-revving performance. These engines provide good low-end and mid-range power, making them suitable for cruising and relaxed riding style.
Transverse Inline Array: Honda CB series motorcycles, among others, feature transversely mounted inline engines. Inline engines are known for their smooth power delivery, high-revving capabilities, and strong top-end performance. They often provide good horsepower figures and can deliver a balanced combination of power and torque across the rev range.
Flat/Boxer: BMW motorcycles are well-known for their Boxer engines, which are horizontally opposed, flat-twin configurations. Flat engines offer a low center of gravity, excellent balance, and good handling characteristics. They tend to provide smooth power delivery, strong low-end torque, and good overall performance.
Wankel/Rotary: Norton motorcycles have experimented with Wankel rotary engines in the past. Rotary engines are known for their high-revving nature and compact size. They provide smooth power delivery and excellent throttle response. However, Wankel engines are less common in motorcycles today due to certain design challenges and complexity.
Ultimately, the "best" engine configuration for performance depends on personal preferences, intended use, and the specific characteristics desired in a motorcycle. It's important to consider factors such as power delivery, torque, weight distribution, and the riding style you prefer when evaluating engine options.