look into a dual-sport bike. if you have 0 hours on a motorcycle right now, you will most likely drop the bike. seriously. they're meant to be dropped, they're cheap, and nobody's going to steal it. you can practice on it until you get sick of it, then upgrade to a sport bike.
unless you really REALLY want a sport bike. there is a HUGE difference between a gsxr750 and a ninja250...the gsxr has WAY too much torque for a beginner. the ninja 250 is easy to ride, but once you start learning how to ride you're going to want to upgrade to a 600 quick. the 250 will be boring after 6mo - 1yr
the gs500 is a very popular beginner bike, and isn't much more expensive than a 250.
you also might want to look into the older CBR's - F3, F4 or a 2000'ish gsxr-600. these have relatively low seat heights which will give you more confidence. how tall are you?
take a motorcycle training course. this is the single best thing you can do if you have no miles under your belt.
cbr F3
gs500
ninja 250
gsxr 600
you can find all these bikes under 3,000 if you're patient.
my main points:
-don't spend a lot of money on your first bike
-
take a rider safety course
-find something comfortable. you will notice that some bikes have a more aggressive riding position. it will hurt your back, shoulders, and arms
-motorcycle forums - read others' "crash" stories so you can learn from their mistakes
-don't get cocky or overconfident and upgrade to something bigger until you're ready. you will know when you're ready for a bigger and faster bike
-buy proper riding gear. a FULL FACE helmet, leather gloves, leather jacket, riding boots, and if you have money...leather pants
-if you don't have medical insurance, get it now
riding a bike in LA could be nuts. make sure you practice somewhere safe. other than what's stated above, good luck with your search and RIDE SAFELY