Im now on my 3th 3AJ tenere and I love it..
Im busy with a rebuild and hope

to have it finished this summer..
fuel must be about 400 km on a tank, depending on your wrist.. 460 was my maximum..
my first 2 bikes were standard and had (I think) 15/ 43, because my current bike is somewhat "bigger" (yes still a 3AJ) Ive opt for a larger rear sprocket, 45 or 46, coming to think of it, it might even be 47..
anyway,
I did had problems with my first 3AJ, because it was standing outside in rain and all sorts of crappy weather..
keep an eye on the coil & lead/ sp-plug cover..
other than that do you regular maintenance and you should have no problems, the 3AJ, specially the one's build after '91 are the last bunch..
these were mostly red/ orange white and have a slightly larger oil-cooler.
my bike as it is now:
have a fairing of a WR450rallyraid waiting to fit it..
but loads of small things need to be done first..
and.. still looking for a complete 3TB/ 4PT engine...
anyone.. please..