Ok, so ive been looking at getting a honda shadow 650 or yamaha v star 750. Something in that range. I've been getting offered bikes at times in the $3000 range that have 140,000 miles on it. and bikes for about $5000 that have 20,000 miles on them. at how many miles does the bike start having problems and is no longer worth the price?

also, what else should l check on the bike besides miles? tips please.

newer bikes can go forever if their maintained properly. With very basic maint like oil changes, air filters & spark plugs we put 50,000 miles on vstar (Yamaha) 1100, & roadstar 1700. No problems, & we look to get many more. l would say though that l wouldnt buy a bike with more then 30,000 miles on it as there r plenty out there in that range. When l see 70,000 Im thinking overhaul & did that person maintain bike.
As for prices, look at kellys blue book & compare with what their selling price is. Also a dealer will give some sort of warr on a used bike.
and go here for a used motorcycle buying guide.
http://clarity.net/~adam/buying-bike.html
also, why buy a real old bike, even a completely rebuilt 1960 vw runs like it did brand new, it still runs like a 1960 vw. You can get a 2000 vintage bike in those same ranges u listed above.

l would have a shop take a look at it before l buy And l would try to put a few miles on it before l buy. When a Bike is over 100,000 it is time to have the bike worked over top to bottom from the top end to the lower case & tyranny there r a lot of parts that have a lot of ware on them that need to be replaced just like a car.
So if u looking for a project bike high miles r ok but if ur ready to ride go with a low mileage bike. It is hard to pin point a price on a bike how well was it taken care of how dose it look & how was it ridden If they used it to show off that put a lot of high rpms on the motor so the mileage may be 20,000 but the motor really has 40,000
short trips put a lot of wear & tear on a bike allot. best deal is low miles with more open rode time.

Modern motorcycles last a long time, just like modern cars. A bike with 140,000 miles on it might have many years left in it. But u worry about things inside that wear out--the clutch, rings, valves, that kind of thing. You take a calculated risk that u might have to spend some big money in the next year or two. A bike with 20,000 miles is barely broken in.

To me, l would rather pay an extra $2000 to make sure the bike is relatively new & there r many miles before problems show up. But that is because l have the extra money. Your decision might be different.

A lot depends on the bike & the owner. If it is clear the owner really loves the bike & has service records & keeps it in tip-top shape, then 140,000 miles is a lot easier. l looked at a bike a couple of years ago where the owner had records of taking it to the dealer every six months for the last 15 years, plus a file with every service invoice showing everything that had ever been done to it!

As for buying a used bike, there r lots of excellent web pages on this. Just Google 'Buying a used motorcycle'. There is stuff in those pages that l would not have thought of, like looking for cupping on tires to make sure the wheels r aligned.

Cruisers last longer than sportbikes, in general, because of the way they're ridden. Cruisers r about laid-back, relaxed riding, so they're not only longer-lasting, they're safer!

Good luck!