NAGOYA--They are uncomfortable to ride and can carry the risk of death, but motorcycles made before World War II have a tight grip on a certain group of aficionados in Japan.

These collectors spare no time, labor or money in their passion for riding the prewar vehicles.

One of them, Osamu Kato, a 76-year-old proprietor of a skewer-grilled meat restaurant in Okazaki, Aichi Prefecture, was recently seen pedaling what appeared to be a bicycle. But then, a dry, fluttering sound reverberated in the surroundings.

He had turned on the engine of his ride, a 500cc Rudge Multi motorcycle made in Britain in 1912.

Kato said he has been collecting prewar motorcycles for more than three decades.

For about 20 years, he had visited a shop in a town in the Oku-Mikawa area of northeastern Aichi Prefecture after learning that the Rudge Multi had long been on display there.

He took over ownership of the motorcycle last year.

Kato has a fleet of 10 vintage motorcycles, many of them from the prewar period, including a 1914 Triumph from Britain.

The majority of their manufacturers have already withdrawn from the business or closed down. With replacement parts no longer available, Kato has asked an acquaintance who works for an ironworks to make ones manually if the motorcycles break down.

He refrains from driving his two-wheelers on rainy days and on hot days to prevent overheating. After the engine stopped on one ride, he waited for about an hour until the engine was cold again.

Just starting an engine involves a variety of operations.

“How well I can operate my motorbikes all depends on my skills,” Kato said. “That gives me pleasure and relief from stress.”

Another Kato, who lives in Ichinomiya, Aichi Prefecture, has a separate fleet of seven vintage motorcycles. Four of them, including a 1926 Sunbeam from Britain and a 1929 Harley-Davidson from the United States, were from the prewar period.

Yoshichika Kato, 63, who sits on the board of directors of an apparel company, has so far ridden on more than 30 different motorcycles.

“I like the history of these motorbikes, which escaped wartime requisition and have survived to this day,” he said. “They are indeed a cultural heritage. I am just their current owner, and I am willing to hand them over to the next generation in time.”

His 1925 Triumph is believed to have been used by a Kyoto kimono fabrics dealer for delivering goods. Kato took over its ownership after learning that a dismantling company had acquired it when the fabrics dealer closed down.

The Triumph’s weak frame bends and vibrates terribly while the vehicle is running. It also has weak brakes, which do not allow it to stop immediately. And a gas lamp serves as its headlight.

“When I ride this one, I put my heart and soul into doing so, at the risk of my life,” Yoshichika Kato said. “It feels nowhere near comfortable. But, come to think of it, is there anything nowadays that requires all of your five senses to drive? This vehicle gives me a different level of experience that you can never get anywhere else.”

The Goody Motorcycles outlet in Kita-Nagoya, also in Aichi Prefecture, specializes in old-style two-wheelers. Popular Honda, Kawasaki and Suzuki models from the 1960s to the 1980s are on offer at prices ranging from 5 million yen ($47,000) to 7 million yen ($66,000), said Yoshinobu Kimura, its 48-year-old proprietor.

He said, however, that foreign models from the prewar period cannot be priced, partly because they need extensive repairs before they are road-ready.

Kimura himself is a collector of U.S. models, including a 1935 Harley-Davidson. He said he spent more than 10 million yen on another Harley-Davidson from 1946.

His proudest possession is a 1924 Indian that was once owned by U.S. movie star Steve McQueen. Kimura cares so much for the motorcycle that he changes its engine oil after every 50 kilometers it travels.

“Vintage motorbikes are extremely inconvenient and uncomfortable to ride,” he said. “But when you are driving them, they make you feel the same way someone else must have felt when they were riding them a very long time ago. I think that’s the true joy of riding them.”

Wakka Project, which organizes volunteers, has been holding an annual event in autumn to bring together vintage motorcycles in Tsushima, also in Aichi Prefecture. A gathering is expected in autumn this year as well.

Thirty motorcycles from in and outside Aichi Prefecture were assembled at the Vintage Bike Run in Tsushima event last year. Half of them were prewar models, and they made demonstration runs.

“Even uninterested spectators looked surprised because rare motorbikes, which you typically only see in a museum, actually ran,” said Takahiro Torikoshi, the 36-year-old leader of the project.