Hi Chris and co.
Are you mad - yes, but aren't we all? Or we wouldn't be doing this kind of stuff - otoh, you ARE double mad...
anyway, I'd suggest not worrying to much about the oil. Wherever you go there will be oil, and in varying grades brands and qualities. Short of carrying vast quantities of oil, which is just simply silly, use whatever there is. The old Triumphs are supposed to use straight weight oils etc more because that is all there was at the time than that it is BETTER for the bike.
Witness BMWs changing suggestions for the SAME bikes over the years. I just use 20w-50 on my 86 R80G/S, the best oil there is available on the spot when needed, and I've had no problems. OTOH, it's consumption is normally about 3 1/2 liters per 5000km - in other words the oil change.
Also finding straight weight oils even in developed countries is really tough, and in the third world it could well be impossible.
I think over the long haul that you will get better performance and engine life with multi-grades and additives than the plain old straight stuff. Of course that could start a long discussion, but fwiw that's my humble opinion...
You have added good easily obtained and replaceable oil filters haven't you? And oil coolers? Both will help a lot, especially on old air-cooled engines under a big touring load and over a long distance in the heat. My G/S never overheated, or showed any sign of it, with the standard BMW cooler, even in 50 deg Celsius temps.
Good luck, and keep in touch! Love to hear how you go!
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