136k is not high milage for a wing! That said, as for any vehicle of that vintage, you must deal with normal wear and tear, and especially aging.
I'd verify that the following major items were attended to around 100k:
-Changed timing belts and tensioners
-Inspect play (drive line slack) in rear wheel hub... the rubber dameners are pretty worn by then.
-Remove and inspect drive shaft, inspecting splines for wear, proper lubrication.
-Inspect rubber boots to driveline, and rear shocks
-Inspect clutch slave cylinder
And then the typical stuff:
-If stock Honda alternator, then verify that it has been serviced in past 20k miles (eg Brushes and bearings ok)
-Change all fluids (clutch, brake, cooling, rear drive oil, fork)
-Change all filters (carb, sub carb, cruise, fuel)
-Change tire valves (preforably to all-metal type)
-Inspect wheel bearings
-Inspect brake pads, and especially the slider pins
-Verify bike runs smoothly at all speeds.
