Here are some photos of my bike which I purchased for $200. I charged the battery, changed the oil and filter, and it fired up 4th kick. Made a terrible clatter and wouldnt rev properly, but I rode it for a day and a half like it anyway because it was still quite fun.
Eventually I got around to checking the valve timing, which it turns out was out quite a bit. Like 3 teeth on the camshaft sprocket! Its a miracle it ran at all, also the valve clearances were about 3mm which is probably what stopped the valves bending worse than they did. I corrected the valve timing and set the valve clearances and apart from the inlet valve sticking occasionally (the piston hits it and shuts it) it was quite good.
It wouldnt idle properly, but this turned out to be a mixture problem as well as a possible leaking inlet manifold gasket. Also I lifted the needle a notch as it was far too lean. A run of 120km (trip to a nearby town) has solved the inlet vavle sticking open, so the valve guide is probably had it by now, but I will do a top end rebuild later if necessary.
Off my first two tankfuls I got aproximately 80 mpg (or 29 km/l or 3 l/100km) and 70 mpg (or 24 km/l or 4 l/100km), respectivley. Not bad economy for a $200 bike! The first tank was mostly around town and with the carb set too lean. The carb is still too lean, so I will lift the needle another clip, but really I need to check the mainjet and probably replace it with a bigger one.
The only problem currently is the clutch wont disengage properly (I suspect the previous owner has left a ball bearing out of the clutch pushrod mechanisim, or it could be an adjustment issue, checking soon), and the camchain is stretched beyond use.