RE: How to take out cylinder liner of DZ170 ?
You might need a little more heat than a hair dryer to get the case to expand enough. I have a toaster oven in my shop for use on stubborn bearings and liners. If you are comfortable doing this kind of work and have a good pair of welding gloves to keep from burning your hands a preheated oven to 300F and put the stripped down case in there for 10 to 15 minutes time can make life easier on you. If you are not comfortable doing this then maybe the YS agent in Australia would be a good bet.
Spaceworm - What you describe would work on the YS 2 strokes, but not the YS 4 strokes.