Harley-Davidson has made an equity investment in Alta Motors, a move that accelerates its ambition to bring an electric motorcycle to market before 2020.

The partnership with Alta, Harley President and Chief Executive Matt Levatich said, will help Harley “bring new riders into the sport,” which analysts say is a must as traditional riders age out of the hobby.

The size of the investment was not disclosed. Alta, based in Brisbane, Calif., is a respected manufacturer of high-performance electric street bikes and dirt bikes including Redshift motocross and race bikes.

Harley, the country’s leading motorcycle manufacturer, has given the name LiveWire to its future electric motorcycle, unveiling a prototype of the fast-accelerating machine in 2014.

The Harley-Alta deal may be partly a response to a 2015 agreement between Polaris Industries and electric motorcycle manufacturer Brammo, which was itself inspired by Harley’s LiveWire project.

Polaris, a $5.4-billion-a-year power sports juggernaut that makes snowmobiles and other recreational vehicles, and the Indian Motorcycle brand of two-wheelers, said in January 2015 that its acquisition of Oregon-based Brammo was made possible by Harley’s electric ambitions.

“Ironically, we may have to thank Harley for opening up a market opportunity for us,” Polaris Chairman and CEO Scott Wine said at the time.

A company representative told the Times late Wednesday: “Indian will be in electric powertrains in the future,” but declined to provide details.

“Indian understands that’s where customers are going to go eventually, and the company has the ability to be there when it makes sense for its riders and the overall Indian Motorcycle business,” the statement said.

Harley appears to be on a faster track. In a letter to investors in January, Levatich characterized the electric motorcycle market as “in its infancy today,” but he emphasized Harley’s eagerness to develop technology.

That prototype, although stylish and containing some obvious Harley DNA in its design, offered a poor combination of high top speed and low battery range — good for photo ops but unlikely to attract buyers.

The bikes that will result from the Harley-Alta partnership will be “urban electric motorcycles,” Alta said. It did not specify size, power or range.