12 bar and cage you can check these spots out:
freestyleingenuity.com
stuntfactory.com
warpedtoys.com
you find lots more links from there.
Rim and forks, check this guy out: Long Beach Motorcyle Salvage 562-436-1889. He's got shops across the nation he deals with.
REMINDER
Nobody crashes backwards, so these parts maybe hard to find.