[spooph]

Good stuff here! As mentioned, keep an eye on the tires and brakes, they can tell you a lot about a bike's wear. General cleanliness of the bike (look inside, by the handlebars, and see what it look like behind the fairings). Test ride it, test front and rear brakes independently. Good idea about mentioning to take it to a mechanic to have it checked out, that will usually expose any shady dealings.

However, as far as your original question goes, how many is too many? Um, is there such a thing? A more accurate question would be: How long can the engine run without oil. And the answer will probably be around 30 minutes or so.... What I'm trying to say is that these bikes will run forever with proper maintenance.... So you're really just looking for evidence of lapses in maintenance...