Pocket bikes are miniature motorcycles -- powered, for the most
part, by oil- and gas-burning engines similar to those used in
chain saws, weed whackers or other small motorized tools -- and
they look just like the real thing.

The snazziest models cost thousands and are made in Italy, but
the ones that are selling by the container load run from $200 to
$500. They come from China, among other places, and are getting
snapped up by eager teenagers and, in some cases,
not-so-teenagers.

At Broadtek LLC, a South San Francisco firm that imports them,
the cardboard cartons containing the small bikes are stacked to
the ceiling of a tall warehouse and are quickly going out the
door to eager customers.

In Walnut Creek, Eric Rahin, owner of Sonic Scooterz, says he's
selling them in droves -- "from college students to people in
their late 50s. It's basically a toy to have some fun with."

Manufacturers say the bikes are supposed to be used only on
closed race tracks, private roads or any other place where there
are no public traffic laws and, more important, no big cars or
trucks to run into you. Many buyers follow that advice.

But now you see some of these new pocket bikes zinging in and out
of parking lots, up and down residential streets and,
occasionally into the side of a car. And therein lies the rub.

"It's very difficult for a driver (of a car) to see one on those
bikes, because of their low height," said San Francisco police
Lt. Kitt Crenshaw. "We've had several accidents in the last few
weeks, and people went to the hospital."

The pocket bikes have a top speed of about 35 mph, but can be
souped up to go faster. They evolved from tiny but highly
sophisticated racing bikes that campaign on European race tracks
and are sometimes used as training vehicles for Grand Prix
motorcycle racers.

The bikes are faithful imitations of popular normal-size street
motorcycles, which, for marketing reasons, are faithful
imitations of pure race bikes, down to the disk brakes,
handlebars, chain drives, twist-grip throttles and electronic
ignition.

The little bikes weigh about 50 pounds, stand about a foot and a
half high and can easily be put in the trunk of a car. They have
tiny engines -- 47cc or 49cc displacement, less than 1/20th the
size of a big motorcycle. And they are enticing.

"It's a fun little thing to ride," said Matt Damon, a 21-year-old
salesman in a Martinez pet store. "It's a whole lot cheaper than
a $6,000 or $7,000 big bike. For years now, I've been riding
different types of motorcycles, but it's more like the small
bikes are a fun thing, instead of just transportation. And it's
easier to maintain and burns less gas."

But Damon did admit, "I took it for a ride down the street and
got pulled over. The officer was kind of nice about it. But I got
a ticket."

Police departments in the Bay Area and elsewhere in California
have been cracking down on the little two-wheelers, saying they
are a major accident waiting to happen. No police agency could
come up with information about any deaths caused by pocket bike
crashes, but police want them off the public roads before the
inevitable happens.

"Their numbers are starting to increase," said Milpitas police
Officer Jay Johnson, who was assigned by his department to look
into the phenomenon and ultimately write about it for the weekly
Milpitas Post. "Most of the complaints we're getting is that
drivers can't see them or there'll be a group of them racing, or
they're running stop signs."

For a while, though, until Johnson began studying up on the
subject, and the California Highway Patrol sent out a memo
clarifying just what is and what is not legal about the bikes,
confusion seemed to be paramount.

In fact, it shouldn't be. On many bikes, there's a decal right
there on the gas tank that says these things do not conform to
"federal motor vehicle safety standards."

After a lengthy consult with the state Vehicle Code and the
Department of Motor Vehicles, the CHP explained that the bikes do
not meet a number of standards required for all vehicles
registered in California -- the most telling example being the
stipulation that "headlamp height (be) between 22 and 54 inches."

Technical problems aside, it's the safety issue that concerns
authorities.

"We're really concerned about these things mixing with traffic,"
said CHP spokesman Steve Kohler. "If you think about it,
something that small is difficult to see, when it's mixed in with
cars, trucks and buses. Drivers don't even see full-size
motorcycles. There's no way they're going to see these things."

Or, as David Edwards, editor in chief of Cycle World Magazine and
a man who puts about 20,000 miles a year on motorcycles, said:
"When you get out in city traffic, you'll be at more risk than on
a full-size motorcycle. But they only hold (a little) gas, so you
won't go too far. And they're noisy as hell, so at least people
will hear you coming if not see you coming."

- Michael Taylor, Chronicle Staff Writer