Is it 1 1/8 looks like it is and Whats the serial, im guessing 1999ish, im not sure of value, diamond backs were never worth very much and 24" BMX were and still are pretty popular for racing these so called "DJ" bikes have only been around for a few years, and have very little similarities traditional bmx frame IMO. Im assuming thats a cast steel 3 piece which i personally like them they are not favored at all amongst most. Overall id say its worth maybe 150$ really just depends on the market, this was probably made before DB sold out so its not worthless. Someone over at BMX museum may pay more. But its by no means rare.
EDIT: it sounds like im bashing but im not i personally like DB just for some reason most dont so the values have kinda dropped Its a good looking bike for sure