Thanks for your input. My focus is on maximizing the expected value of miles I can ride per dollar I put into it.

Is it currently unlikely that this bike will make it a long distance, and will reboring the engine / replacing piston and rings make it significantly more likely to reach CT? (Will the repair take it from 50% likely to 90%? Or from 85% to 90%?)

I've heard others indicate that it would be no problem to start with the current amount of oil burn, and indeed some who have started an Africa trip with a bike that burns comparable amounts of oil. I'm no expert, but it still is a bit disconcerting to be going through that amount of oil. Repairing it is expensive, but compared to the cost of the entire trip might not be too big of an expense, so I'm still considering it.

Also I would not be shipping this bike home; I'd try to sell in South Africa or en route, but I'm not counting on that. Another reason I'm reluctant to put a lot of money into it.

I realize this perspective ("how far til the wheels fall off?") is discomforting, since we generally put so much care into our bikes. And I am leaning towards fixing it (just feels wrong to not do so), but the expense is hard to justify unless it's very unlikely to survive long.

I also consider that for the cost of the engine repair, I can buy a 125 in west Africa.

Still weighing the benefits... Would be great to get some more perspectives.