PORTLAND – A surge of “pocket bikes” in Maine has led to a spate of complaints about noise and underage riders and is raising questions about which motor vehicle laws apply to the vehicles.

A fad among bike enthusiasts, the minimotorcycles began showing up in Maine a few months ago. The machines are 2 feet and under and can go up to 30 mph.

“We’ve been chasing them around, off the street, all week long, one call after the other,” said Sgt. David Smith of the South Portland Police Department.

But fans say the bikes look good and are exciting to drive because they are so low to the ground. At several hundred dollars, the bikes are also a lot cheaper than real motorcycles.

VIP Discount Auto Center in Portland has sold 38 of the latest model, Electra Sports Style Gas Racer, for $399.99 each, in the last two months.

“Maybe they can’t afford the full-size ones,” said Bob Morneau, the store’s general manager.

With one-cylinder, gas-powered motors suited for weed whackers, the bikes aren’t particularly fast. But police say riders, typically teenage boys or young men, are tearing through parking lots, weaving through traffic jams and spooking pedestrians.

Earlier this month, Portland police issued summonses to a 22-year-old rider for an unregistered motor vehicle and to a juvenile for operating without a license.

They issued another summons to a 21-year-old man on a downtown street for operating a vehicle after suspension, operating an unregistered motor vehicle and driving to endanger.

“That’s amazing to me that somebody would go through an intersection downtown on one of those things,” said Sgt. Gary Rogers.

Police also say many models – mostly Chinese copycats of Italian pocket bikes – do not have horns or lights, and riders do not always wear helmets.

But pocket bikes are so new to Maine and other states that questions persist on how they are categorized.

State statute says nothing explicit about pocket bikes – also known as pocket rockets. But the machine’s maximum speed – typically advertised at under 30 mph – and power – an engine with a displacement of no more than 50 cubic centimeters – means it should be registered as a moped, said Deputy Secretary of State Chip Gavin.

Consequently, operating a pocket bike requires a valid driver’s license – just like a moped – meaning children under 16 cannot ride them on public ways and parking lots.

At VIP Auto Center in Portland, sales representatives give pocket-bike buyers a disclaimer saying the vehicles are meant for off-road recreation.

Even though state statute indirectly addresses pocket bikes, a working group from the offices of the secretary of state and the Department of Public Safety is considering whether such “nontraditional vehicles” need further legislative oversight.

“We want to be prepared if these vehicles are here to stay, that they can be operated in a safe way … and we also want to be sure that the roads of Maine are safe for everybody,” Gavin said.