Without taking into account the context of a particular application, the initial question is incomplete. It’s like asking “why do oranges taste better?”
@TwinTurbo, the OP’s question seems to relate to motorcycle engines vs. car engines. From his earlier post:
“Perhaps I’ve been misinformed all my days. [shrug] I was told that motorcycle engines are less efficient, as evidenced by how hot they run. But they rev WAY higher, and are burning the same petrol. The 2008 Susuki GSXR 1300 makes 194 HP with a 1298CC engine, whereas the 2015 Civic makes 143 from a 1798CC engine. The F650 makes 362HP with 6,800CC, or 0.0532 HP per CC. The aforementioned 'busa yields 0.1515 HP/CC making it 300% more efficient. Curious.”
And as others have pointed out, he is confusing “efficiency” with “specific power,” which are apples and oranges.
Oranges don’t alone. Bananas do too because they also have “a-peel”.