I have a newbie question for you.
I'm considering buying a 2004 Yamaha TTR600RE- a single-cylinder, air-cooled dirt-focused dual-sport bike. It's perfectly set up for adventure touring, which is what I want it for. The engine has 11k miles on it (not the original engine).
However, the owner has said it burns about a pint of oil every 400 miles on the freeway, which doesn't seem to bode well for any long distance trips in remote places (I'm planning a "RTW"-type trip).
The owner also points out that "The bike sometimes lets out a puff smoke from the exhaust on starting so the valve seals are worn its not a problem did a 1500 mile trip last september."
Are the valve seals the likely culprit? If not, why else could this bike be burning oil? Would a mechanic, upon breaking open the engine, be able to say definitively whether the valve seals or piston ring or anything else are at fault? What would the ball-park cost for replacing the valve seals and piston ring be? (closer to $200 or $500?) How likely is it that the cause of the oil burning would not be properly diagnosed?
If worst comes to worst, what would a ballpark cost for an engine rebuild / new engine plus installation be?
Normally, I'd look for other bikes (and I am still looking), but the bike market where I live is quite small and the TTR is relatively inexpensive and seems to fit the bill in almost every other way (includes many otherwise expensive upgrades for overlanding). So if a valve seal / piston ring replacement would probably do the trick, I'd go for it. I'd appreciate your thoughts.