i know that this is quite a old conversation but if you still have the dt125 and you want more power, a yz125 1989-1993 engine atleast fits perfectly with the swingarm and you just have to make like 2 head mounts from sheet steel, i did that to mine cause well the cylinder fucked up and i had a yz laying around because i was doing a dyz project anyway, so i sold my other damaged dt125 frame and just built it in my main bike where i kept the dt frame for plates and the frame number and everything else on it is from a yz
L
Lukas
@Lukas