Well out of good fortune a friend of mine HAD a 600 Bandit but totaled it doing wheelies. He told me a salvage yard would help him out and come pick it up and take it away....for $700!!! I told him I would pick it up for nothing.....Anyway, I have two gixxers, '89 and '90. The motor in the '89 was suspected low on compression (so i thought). The '89 became my sons future bike and figured having a somewhat detuned motor would be fine. So I took my new '96 Bandit 600 donor motor and slipped it right on in my gixxer. Fits like a champ, there again it is the same motor on the outside. So you should have no problem putting a 1100/1200 motor in your bandit. One thing though, some 1100's have hydralic clutches. I havent seen the 1200 Bandits lately, do they have hyd clutches??? If not, that might be just what your looking for as long as you stay with apples and apples. I myself am looking for an 1100 for my '90....