Simplify the following text for a Grade 9 native English-speaking person.
Original: After World War II Bridgestone started manufacturing motorcycles , but its main income was from supplying tyres to its rival motorcycle makers such as Honda , Suzuki and Yamaha and it was later decided to cease motorcycle manufacturing .
Simplified: After World War II , Bridgestone started manufacturing motorcycles . But its main income was from supplying tires to its rival motorcycle makers such as Honda , Suzuki and Yamaha .