The seatpost is 24.8mm on a DB Pro-Star, my first BMX too and I've owned/built a few.
[ Attachment: You are not allowed to view attachments ]
[ Attachment: You are not allowed to view attachments ]
[ Attachment: You are not allowed to view attachments ]
[ Attachment: You are not allowed to view attachments ]
[ Attachment: You are not allowed to view attachments ]