It is a V-twin engine with a displacement of 131 cubic inches (2,147 cc). This engine is capable of producing impressive power and torque output.
Regarding the most powerful motorcycle engine, it's worth mentioning the Dodge Tomahawk, which is a concept motorcycle featuring a modified version of the Viper V10 engine used in Dodge sports cars. The engine has a displacement of 8.3 liters and produces an astounding 500 horsepower.
As for the most expensive motorcycle engine, it can be challenging to determine a specific model as prices can vary depending on various factors such as customization, exclusivity, and rarity. Expensive motorcycle engines can often be found in limited-production or custom-built motorcycles from high-end manufacturers such as Harley-Davidson, Ducati, or MV Agusta, among others.
It's worth noting that the motorcycle industry is continually evolving, and new engines and models are being introduced regularly. Therefore, it's advisable to consult up-to-date sources and motorcycle manufacturers for the latest information on powerful and expensive motorcycle engines available on the market.