moontan, i have a zrx1200, not a fz, although it sure is a nice bike and would have been a toss up if they had an fz in stock when i purchaced the kawsaki. i understand the yamalube 20-40 is real popular with the yamadudes!
I have a 2000 R1....basically the same engine as your FZ1. I have been pretty happy with Motul 300v sport. Now I am using Redline 5w 30. So far Im pretty happy with the Redline....very smooth shifting.
I have a 2003 FZ1 and use the amsoil 10W-40. I have no complaints with the use of amsoil in my bike. I switched to amsoils after 1000 miles last year and then rode out to South Dakota last summer, 2200 miles total and no oil comsumption.
I would recommend using the yamalube for break in purposes and then switch to the amsoil. There are mixed opinions on the use of a synthetic oil in an engine with a thousand miles, however the opinion is that the engine is well broken in by 600 miles and the use of synthetic oil is appropriate.
Does an FJR count? Does to me! Been using RTS with great success. One of the things that's been nagging at the back of mind is using XD-3 0w-40 or maybe even GC. Both are not energy conserving and both are relatively thick oils. I don't know...
Check out http://www.yamahafz1oa.com/forum/
Lots of good, well thought-out info from a large group of owners/enthusiasts. (I've got the hots for a FZ1 or similar multi-purpose bike, and I've been checking out lots of different sites).