at 170 i wouldn't recommend getting a 125. go with the 250f or 250 2stroke. the 125 will have to work more and seem slower to you
dont think it can be done . they are as good as they come
Haynes do suzuki dr125/gn125/gz125 (88-05) e-bay 12 pound.
I have been up to 75MPH along the fosse way after my 1st service with bout 1000 o nthe clock.. always easier on a warm day witha hill to hand :P