A vehicle making method which comprises: a preparatory step of preparing first and second combustion engines (E1, E2) having respective connecting portions with exhaust devices (D1, D2), which connecting portions are different from each other, but the remaining portions, are formed to have common structures, and two, first and second exhaust devices (D1, D2) having different characteristics and corresponding respectively to the first and second combustion engines (E1, E2); and an assembling step of connecting the combustion engines (E1, E2) with the corresponding exhaust devices (D1, D2) to provide two types of first and second vehicles (M1, M2) having different output powers, wherein during the preparatory step, the first and second combustion engines (E1, E2) and the first and second exhaust devices (D1, D2) are prepared, in which the first exhaust device for a high output power is connectable with the connecting portion of the first combustion engine, and the second exhaust device for a low output power is connectable, but the first exhaust device is non-connectable, with the connecting portion of the second combustion engine; and during the assembling step, the first vehicle of a high output power is assembled by connecting the first exhaust device with the connecting portion of the first combustion engine and the second vehicle of a low output power is assembled by connecting the second exhaust device with the second combustion engine;the first and second combustion engines (E1, E2) and the first and second exhaust devices (D1, D2) are connected with each other by means of coupling structures for connecting one of them with the other; and due to the difference in coupling structure between the first and second combustion engines (E1, E2), the second exhaust device of the low output power is connectable with the connecting portion of the second combustion engine, but the first exhaust device of the high output power is non-connectable with the connecting portion of the second combustion engine; characterized in that the first and second combustion engine (E1, E2) and the first and second exhaust devices (D1, D2) are connected with each other through coupling members (130, 132) each having a tubular outer wall engaged in a tubular inner wall; and because the coupling members (130, 132) of the first and second combustion engines (E1, E2) are formed having been reversed in orientation relative to each other, the second exhaust device of the low output power is connectable with the connecting portion of the second combustion engine, but the first exhaust device of the high output power is non-connectable with the connecting portion of the second combustion engine. a preparatory step of preparing first and second combustion engines (E1, E2) having respective connecting portions with exhaust devices (D1, D2), which connecting portions are different from each other, but the remaining portions, are formed to have common structures, and two, first and second exhaust devices (D1, D2) having different characteristics and corresponding respectively to the first and second combustion engines (E1, E2); and an assembling step of connecting the combustion engines (E1, E2) with the corresponding exhaust devices (D1, D2) to provide two types of first and second vehicles (M1, M2) having different output powers, wherein during the preparatory step, the first and second combustion engines (E1, E2) and the first and second exhaust devices (D1, D2) are prepared, in which the first exhaust device for a high output power is connectable with the connecting portion of the first combustion engine, and the second exhaust device for a low output power is connectable, but the first exhaust device is non-connectable, with the connecting portion of the second combustion engine; and during the assembling step, the first vehicle of a high output power is assembled by connecting the first exhaust device with the connecting portion of the first combustion engine and the second vehicle of a low output power is assembled by connecting the second exhaust device with the second combustion engine;the first and second combustion engines (E1, E2) and the first and second exhaust devices (D1, D2) are connected with each other by means of coupling structures for connecting one of them with the other; and due to the difference in coupling structure between the first and second combustion engines (E1, E2), the second exhaust device of the low output power is connectable with the connecting portion of the second combustion engine, but the first exhaust device of the high output power is non-connectable with the connecting portion of the second combustion engine; characterized in that the first and second combustion engine (E1, E2) and the first and second exhaust devices (D1, D2) are connected with each other through coupling members (130, 132) each having a tubular outer wall engaged in a tubular inner wall; and because the coupling members (130, 132) of the first and second combustion engines (E1, E2) are formed having been reversed in orientation relative to each other, the second exhaust device of the low output power is connectable with the connecting portion of the second combustion engine, but the first exhaust device of the high output power is non-connectable with the connecting portion of the second combustion engine.