i miss my 04 tdub so much im looking at buying a 01 with 9800 miles this weekend, and im assuming its will be time to tear into it right away for reliability's sake?
10K until overhaul ---I sure hope not. If in doubt do a compression check on the bike, and ride it to see if it's running alright.
I don't know how many miles between overhaul on a TW200 but I have had many small displacement bikes and found that around 15-25,000 miles I get some noticeable piston slap and oil consumption starts to increase. When I don't like the rate of oil consumption I go to the first oversize set of piston and rings and bore out the cylinder.
I'm not sure how many miles for the valves 40-65,000 miles maybe - unless something strange happens before--I would guess that carbon build up and/or the springs getting weak over time would be common causes for a valve job. I plan to remove the head at 25,000 miles and look at the valves. I'm hoping that they (the valves) will last until I have to go to the second oversize of piston and rings. And bottom end should go over 100,000 miles--- I would guess.
But I don't see too many people putting those kinds of miles on these bikes and I don't know if I will live long enough to see that many miles either.
That's one persons wild assed guess based on my ownership of other small displacement bikes.
Do a good pre-buy inspection and good luck.