A BMX stem is what connects the handlebars and forks to the frame.
To fix BMX handlebars, you might need to bend the handlebars back to their correct position. You might also need to tighten the bolt that anchors the handlebars to the bike. Fixes will vary depending on what is wrong with the bike.
Yes, all handlebars have the same diameter out by the grips.
Tighten the stem
Primo strands or Odyssey cs2 race forks
you can searh online on skatehut , winstanleys bmx and dogg scooters are the best.
you probably want to replace them. They can be pretty cheap to buy off the internet.
the fork gyro (if have) and stem and mostly important the headset
It´s the Stem, it holds the bars and match with the frame with the help of a headset.
check for any obstructions on the frame if there is anything get it off
it depends on what the purpose for riding your fixie is...for tricks use a riser handlebar because it allows for the best leverage when doing wheelies or keospins. you should use straight bars when your just cruising
The BMX bike stems are used just like any other bike stems for most any brand. The stems hold together the base of the bike and the steering part or the handlebars.