It’s been a bumpy ride for the custom motorcycle business as sales of pricey, blinged-out bikes skidded with the economy.

But one bike scene is thriving, and that’s been a boon for Ryca Motors in Whittier. The company sells build-it-yourself motorcycles that cost $3,600 to $7,500, or a fraction of the cost of souped-up custom bikes.

Its CS-1 Cafe Racer is the creation of builders Ryan Rajewski and Casey Stevenson, who decided that if they were going to go to all the trouble of building a one-off, they might as well reproduce all the parts and offer them as a kit. The result is a motorcycle with all the style of a classic street racer at a far lower price.

“It’s fun to do customs, but you spend so much time building the thing, and it’s just this one person who has it,” said Rajewski, who fused the first syllable of his first name with his business partner’s to form Ryca Motors. “Unless you’re the top 1% of guys, you don’t make any money.”

Ryca’s CS-1 kit is changing that. Since going into production last fall, Ryca has sold almost 300 of the $2,600 to $3,000 kits. About 95% of them, Rajewski said, are being built by customers, who need nothing more than a used bike, some hand tools and 40 hours to complete the job.

It’s a perfectly timed product for an industry that has seen sales of new motorcycles decline more than 50% over the last three years and many custom shops go out of business.

The CS-1 is built from a motorcycle that has been in production for more than a quarter-century: The Suzuki S40. So many S40s have been manufactured since 1986 that used, low-mileage models can be found for as little as $1,000.

The single-cylinder, 652-cc machine is a tried and true workhorse that, in stock form, is out of sync with modern aesthetics, but transformed into the CS-1, it has a new cool factor that isn’t only winning Ryca customers and turning heads on the street, it’s catching the attention of American Suzuki Motor Corp.

“I’m a 31-year-old male. I would have never looked at the S40 as a bike for myself, but when I saw the CS-1, I totally would,” said Aaron Quesada, senior communications specialist for American Suzuki Motor Corp. in Brea. “When people see the Ryca kit, they’re like, ‘Whoa. I could do that to this bike?’ It creates a lot of excitement.”

Last fall, American Suzuki Motor Corp. lent an S40 to Ryca Motors for a CS-1 conversion. Company representatives were so impressed with the transformed motorcycle that they are actively promoting it to Suzuki’s 950 U.S. dealers as a showroom lure to increase sales. Quesada said Suzuki dealers could experience a double benefit with the Ryca bikes, adding value to the used S40s they accept in trade as buyers upgrade to more expensive Suzuki models.

The CS-1 kit includes 300 parts that can be wrenched into place with common tools. No welding is required. Customers who source their own bikes need to remove the rear wheel hub and tank and send them to Ryca to be modified. A downloadable PDF on the Ryca Motors website and videos on Ryca’s YouTube channel walk do-it-yourselfers through the process.

The CS-1 is capitalizing on the enduring popularity of the cafe racer scene, which dates to the 1960s, when riders individualized their bikes by stripping them to the basics and raced them between cafes. In the coming months, Ryca will make kits for other popular retro styles, including a two-seat, dual-sport scrambler, a flat-track race replica called the Street Tracker and a 1950s-style bobber that’s a hardtail vintage throwback.

Rajewski and Stevenson have known each other since they were in a band together 12 years ago. They shared not only a love of music but mechanical and entrepreneurial spirit as well. Rajewski, 34, was an auto mechanic who had been working at shops since he was a teenager. Stevenson, 38, was a NASA engineer. They formed Ryca Motors in 2009 as a one-off custom shop.

But, Stevenson said, “It’s more satisfying knowing there are hundreds of CS-1s around the world than to build a bike and sell it for $100,000 to a rich dude.”

susan.carpenter@latimes.com