Actually many theories on engine break in, but one makes the most sense, do the first oil change early.
No experience with brand new motorcycle, 4 wheeler or snowmobile break ins, I've always bought used.
As for cars, there are a variety of ways to break them in, including special break in oils for freshly rebuilt or crate motors.
With cars my family has a variety of ways to break in engines. My uncle feels the drive it like you stole it is best. However he usually sells them before the first tire change. My dad, an engineer with a big auto company for decades, felt a variety af engine speeds were best, no cruise control in the first 2,000 to 5,000 miles. He had cars from the 80's and 90's with mileage in excess of 100k miles with no major issues except for normal maintenance, some of which were known for reliability issues with engines and transmissions. One of his favorite cars that he kept the longest was a 1990 Supercharged Grand Prix 4 door, he sold it at 140,000 miles, still ran like new.
I think the latter technique with an early 1st oil change is best for any ICE motor.
No experience with brand new motorcycle, 4 wheeler or snowmobile break ins, I've always bought used.
As for cars, there are a variety of ways to break them in, including special break in oils for freshly rebuilt or crate motors.
With cars my family has a variety of ways to break in engines. My uncle feels the drive it like you stole it is best. However he usually sells them before the first tire change. My dad, an engineer with a big auto company for decades, felt a variety af engine speeds were best, no cruise control in the first 2,000 to 5,000 miles. He had cars from the 80's and 90's with mileage in excess of 100k miles with no major issues except for normal maintenance, some of which were known for reliability issues with engines and transmissions. One of his favorite cars that he kept the longest was a 1990 Supercharged Grand Prix 4 door, he sold it at 140,000 miles, still ran like new.
I think the latter technique with an early 1st oil change is best for any ICE motor.