Engine and exhaust system

An engine comprising:

• an engine main body including a first cylinder and a second cylinder;
• a first exhaust pipe that is connected to the engine main body and into which exhaust gas is introduced from the first cylinder;
• a second exhaust pipe that is connected to the engine main body and into which exhaust gas is introduced from the second cylinder;
• and
• an exhaust manifold including a first inlet portion connected to a first lead-out portion that is a downstream end of the first exhaust pipe, a second inlet portion connected to a second lead-out portion that is a downstream end of the second exhaust pipe, and a common outlet portion that leads out exhaust gas flowing in from the first inlet portion and the second inlet portion,
• wherein:
• the first cylinder and the second cylinder are disposed with a first cylinder axis line that is an axis line of the first cylinder forming a V shape together with a second cylinder axis line that is an axis line of the second cylinder as viewed along a crank axis line that is a rotation center line of a crankshaft,
• the exhaust manifold is disposed between the first cylinder axis line and the second cylinder axis line as viewed along the crank axis line,
• the exhaust manifold is not fixed to the engine main body,
• the first lead-out portion and the second lead-out portion face each other with central axes of the first lead-out portion and the second lead-out portion aligning on a same axis line,
• the first inlet portion has a cross section that is orthogonal to the axis line and has a shape constant between a case where the exhaust manifold is at a predetermined first position and a case where the exhaust manifold is rotated about the axis line from the first position to a second position different from the first position, and
• the second inlet portion has a cross section that is orthogonal to the axis line and has a shape constant between the cases where the exhaust manifold is at the first position and at the second position.