Starter clutch???

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.