Picked up an old CT3 Yamaha from a mate for free. It had been sitiing outside long enough to rust the left hand handlebar off, but aside from seized brake cams it is in surprisingly good condition. This being the case, I've decided to try and turn it into an el-cheapo trials bike for classic dirt, with a budget of $600
I've cut and shut the frame everywhere and ended up with a bike that is very similar to a TY175, but with a bit more ground clearance, slightly longer wheelbase and a steeper head angle - traits that are all said to improve the TY.
Next is to narrow and lengthen the CT3 tank and make up the footpeg plates. Following some good advice from JC, I'm after a set of MX125 triple trees. They have more offset and will reduce the trail to somewhere near the optimum for a trials bike.