There are several manufacturers that produce motorcycle and ATV engines for US models. Some of the prominent manufacturers include:
Harley-Davidson: Harley-Davidson is an iconic American motorcycle manufacturer known for producing heavyweight motorcycles. They design and manufacture their own engines for their models.
Polaris: Polaris Industries is a company that produces a range of powersports vehicles, including ATVs and side-by-sides. They manufacture engines for their own line of vehicles, such as the Polaris Sportsman and RZR models.
Honda: Honda is a Japanese manufacturer that produces motorcycles and ATVs for the US market. While Honda is not an American company, they have production facilities in the United States and manufacture engines for their US models locally.
Yamaha: Yamaha is another Japanese manufacturer that produces motorcycles and ATVs for the US market. Similar to Honda, Yamaha has manufacturing facilities in the United States and produces engines for their US models domestically.
Kawasaki: Kawasaki is a Japanese manufacturer known for its motorcycles and ATVs. They also have production facilities in the United States and manufacture engines for their US models locally.
It's worth noting that some smaller motorcycle and ATV manufacturers may source engines from other companies or engine suppliers to use in their vehicles. Additionally, there are companies that specialize in producing aftermarket engines for motorcycles and ATVs, offering options for customization and performance upgrades.