http://www.ducatigirl.com/california/dmv_b_roulette.htmlCan I park in a location where there is only one stall line to the left or right of me?
Other than stall lines for handicapped individuals, there is no talk about stall lines in the California Vehicle Code. This is something that's most likely handled by individual counties. In the case of San Diego County, Article 10, Section 72.150 indicates the following for angle parking: "...the Road Commissioner shall indicate at what angle vehicles should be parked by placing parallel white lines on the surface of the roadway. On such portions of such highways a person shall not stop, stand, or park any vehicle except between, at the angle indicated by, and parallel to both such adjacent white lines with the nearest wheel not more than one foot from the curb or edge of the roadway."
As a San Diegan, I can verify that the folks in them cute little carts are ready and willing to slap a ticket on your bike for angle parking in a spot that doesn't have a white line on both sides. Damned if you do, damned if you don't: If you take up an entire parking stall, car drivers (especially in places where parking is a precious commodity) give you grief about it. If you cut drivers some slack by parking in out-of-the-way places, odds are you'll get slapped with a ticket.
Can I park on the sidewalk?
Motorcycles are considered vehicles by the California Vehicle Code and are subject to the same rules and regulations of any car, so motorcycles cannot park on any sidewalk that is public land. In cities like San Francisco where parking is a problem, enforcement of this law may be lax (as evidenced by a lot of scooters and motorcycles on the sidewalk).
Can I share a metered parking spot?
According to Sargeant Price in "Friction Zone": "As for parking at a meter, a motorcycle's rear tire or fender must touch the curb; and yes, you must pay for the parking space you are using. If you share the space with another car, you could be subject to citation." Technically, it sounds like two bikes sharing a metered stall would be subject to citation if all vehicles are treated equally.
I have heard of cops ticketing bikes sharing spaces, particular where riders congregate and where they want to discourage this congregation. In one instance, the riders decided that if the cops were going to ticket them for more than one bike per space, then they were going to park one bike per space, which meant many spaces in an already too-hard-to-park area were unnecessarily consumed. The cops stopped the ticketing and the riders went back to multiple bikes per spot. Sometimes, only sometimes, reason does prevail.