My K3 uses no oil between 5000+ oil changes and I broke it in on the dyno with 7 miles on the clock.
Sounds like somebody either neglected or beat the shit out of your bike.
How hard is it to do rings? In a word, hard. It wouldn't surprise me if the motor has to be removed from the frame. If it's the valves, chances are you can remove the head with the engine still n the bike. Of course, I've never had the misfortune of having to replace rings or valve guides on a bike, so this is speculation.
Put some heavy weight oil in it so it hopefully won't smoke (as much) and try to find an unsuspecting dealer who will take it off your hands. Ugh.
it could either be your rings or your valve seals. like was said before, the only way to tell which one is to do a compression and a leakdown test. if your compression is low, your rings are shot. if you get a lot of leakdown, it is your valve seals. my 03 doesn't ever burn any oil between my 3k mile oil changes.
How many miles do you have on the bike?? My 03 gixxer has 19,000 miles and I have to add a little oil sometimes.. the dealer says this is normal for a bike that has been ridden even remotly hard.. I have no white smoke tough..