M1100 sharp rear brake !

My bike is new to me, I've only had it for a few weeks
I find the rear brake very sharp, very easy to lock the rear wheel with relatively gentle rear brake pressure. It has Rizoma rear sets fitted.
Is this a common thing ? My previous bike was an Aprilia RSV which had basically no rear brake so maybe it just requires some getting used to ????
Maybe I need to fit some rock hard pads that don't bite as well ??