I am in Kabul at the moment on business and will not be back in Bishkek for a week or so. To get a bike in Bishkek is easy, get the classifieds and a translator, you can pick up a Ural in the 200 range, A Jawa in the 350 range and if you want something else like a japanese Bike it will cost a LOT. That is my experiance, the market is okay but it is high priced and you need to go on sundays. If you just want a small Chinese bike there is a place across from the Osh bazar that sells them brand new in the 500 range, they are about 250cc but you can get around on them. Hope this helps.
Seeing the world,One mile at a time