Unbolt everything from old frame, assemble on new frame, done.
A BMX stem is what connects the handlebars and forks to the frame.
The frame
6
Sunday funday
Roughly 5 lbs.
All "true" BMX bikes are built for 20" wheels, which makes them very similar in size.
You can remove bearings from a BMX frame with a 'mid' bottom bracket without damaging them using a 3/8s rachet extension.
Depends on the bike frame..
Nothing you can do yourself. If it's phrase you've picked up from a sales pitch it means that the manufacturer has come up with a change to the design which he thinks makes the frame better in some way.
uhhm the only thing i would say its that if you want to keep your frame, stop doing that. if your frame becomes damaged, you should replace it. if theres a worn down part of the frame, it will be a point that can fracture from the stresses of BMX riding because it will be weaker than the surrounding areas on the frame.
No. A BMX is almost entirely ridden "out of the saddle" (=standing up), so size doesn't mean that much. (most) MTBs are intended for some seated riding, which makes frame size much more important.
Mostly in China, although their ultra high end pro BMX bikes are made here by private frame builders.