The same rules dont really apply to bikes.
The tend to have a lot harder life, with only a few marques (BMW, Honda only relatively recently) and models (VFR, Pan European, CBR 600, Diversions) being able to take big mileages without looking like like they are going to fall to bits.
Anything over 20k will most likely need the suspension rebuilding front and back, will most likely be due a major service,need new head races, cush drive etc etc. Thats another 1k before you start if you are going to look after it.
The model you are looking at will most likely of spent most of its life on one wheel, so will probably need all of it doing.