In my experience the 1979-1980 subframe is a little narrower than the later model and in addition to the protruding bolts the sub-frame itself makes removal of all but the smallest batteries a bit of a trial. The solution s to put the bike on the centre-stand with a couple of small blocks of wood under the stand and to then remove the bolts and then bear down on the rear of the subframe witht he front wheel secured to the ground - a few other bolts may need to be loosened somewhat - the battery can then be easily removed or inserted.
My experience with y 1984 edition is that the battery can be easily replaced, but bear in mind I have used gel cell batteries exclusively and I suspect that they area little smaller than wet cell batteries.
