The company had sold 4,38,479 units in the corresponding month last year, HMSI said in a statement.
HMSI's motorcycle sales, however, declined 18 per cent to 1,47,258 units last month, from 1,79,456 last year.
However, the company's scooter sales jumped 9.64 per cent to 2,64,385 units, from 2,41,124 in September 2014, it added.
Exports grew 6.64 per cent to 19,089 units against 17,899 in the same month a year ago, it said.