if you're looking for help with a conversion check out a place called the bicycle kitchen.
i don't live in LA but when i visited about a month ago i checked it out and it was a pretty cool place,
bunch of volunteers looking to help anyone who comes in, all the tools you'll need to do what you want and plenty of spare parts.
it's also right across the street from another shop called orange 20 which is also definitely worth checking out.
It was cool to find these places in a generally bike-unfriendly area