solenoid windings/contacts breaking down take the starter motor off and take it to an alternator & starter motor repairer you'll find them in yellow pages or bike mags or get a replacement starter motor secondhand plenty of bike breakers out there.
Dr bob, March 2010
if it turns a bit then there is a series of fast clicks the battery is faulty and not carrying enough amps.get a new good one
adam bike doctor, March 2010
check your battery with amp meter if its o.k its the starter motor