Hi Tango,
sounds like you are facing at least two issues.
Issue 1: As dougyt said, check if electrical power comes down to the starter motor.
Possible errors are bad contact in the starter switch (at handlebar) itself.
Maybe the starter relais (solenoid?) is not working correctly or the small cables from starter switch to relais are in bad condition.
Finally the contacts / coals inside the starter motor are worn and need replacement.
Just as an example:
Starter KIT Kawasaki Motorcycle KZ750 KZ 750 76-83
http://www.ebay.de/itm/270516508179?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649#ht_1432wt_1192
Issue 2: If the starter motor turns but can’t turn the motor it is very likely that the one-way-clutch is defective and needs replacement as described before. You can see in the picture a small gear inside the motor. I understand that dougyt had trouble with that.
If you plan to disassamble the starter motor, first disconnect the battery !!!
Please be very careful when removing the nut that holds the “power cable”. The bolt that sits at the side in the motor must be hindered to turn. If it turns with the nut, stop immediately and think about a mean to hold it in position. If that bolt turns, the small cable inside the motor will be damaged (ruptured?) and that is hard to repair.
Cheers, Michael
