My 90 CBR1000f dosen't start. It runs fine if bump started, it starts if jumped from a running car with starter fluid (but I hear the alternator complain). When the engine turns over it turns over slow and without the help of an additional battery and a running car gets no spark. The battery is new. I have replaced the starter (with a used one) with same results. Plugs and wires are less than 6 months old. Someone here mentioned that it may be the starter clutch that is the issue. As it is an expensive repair to undertake on a guess I asked for further evidence and got no reply. So here I am asking again - Has anyone had starter clutch issues and what were the symptoms?? Does anyone have other ideas?

Thanks in advance.