At what point do you consider a bike to have too high mileage on the clock?

It all depends on a lot of  things , condition , how many owners ? , value , engine size , any  history ? , know the seller etc. .  I find most large jap bikes will do silly mileages , even if  the bike was under -serviced , and some european bikes don"t match -up . After my last three B.M.W. s I swore [literally]  that I will never own another . I  won"t  go into my experiences with  Ducati"s , Morini"s , Urals , Harleys  and a few  Brit. bikes . But I suppose we all buy a lemon  at some point  . As with some cars I have owned  some really cheap bangers have proved real gems . A  1961 B.S.A. Goldflash bought in 1973 for  £ 137  ,off a local dealer ,proved the most reliable second hand  bike  , owned many years , only broke down twice , sold  a couple of years ago for nearly  £ 6,000  . The Ural outfit broke down every  week  , and engine blew -up  after  4 months from new ! . If possible buy off someone you know and treated the bike with loving care .