Coming out of a dark beginning, KTM have made big strides in reliability from the 90's and early 2000's. Especially true of big twins. Early 950's/990's had some problems but more recent ones (1190, 1050, 1290) seem to be going well and mostly trouble free.

We have a lot of KTM twin riders around here...very few do long term travel, but many are ridden unusually hard. I would not buy 2004 to around 2007. Buy a newer KTM for more reliability. Lots of fixes and upgrades have been made in just the last 3 or 4 years.

The singles (640 and 690) had more frequent and more serious problems. If you go WAY back, (mid 90's) the 640's had lots of repeating problems. This model is discontinued but many still on the road. Once a few things are fixed/replaced and sorted the 640 seems OK, but you have to have "The Knowledge" to keep them healthy if on the road for extended periods and far from a dealer.

Early 690's had problems also, from around '07 to '09 or so. More recent 690's seem more trouble free, fewer top end and fuel pump related failures. But like ALL KTM's, they require a knowledgable and careful owner. Keep up on maintenance, do all fixes upgrades pro actively, carry spares for common failures and it should all be good.

Not many KTM's have made RTW trips without at least a few interruptions for
"service".

It's an expensive machine, but relatively lightweight and very fun to ride.
For Europe or USA I would not hesitate to travel on a KTM. But for more remote regions I'd make another simpler, less expensive choice.