Join Date: Aug 2013
Location: Sale, VIC, Australia
It could well be a dodgy solenoid. They can play buggery when they muck up.
I'd also check any earth points on your bike. Between engine and frame, srater motor and engine/frame if applicable and from the negative pole on the battery to the frame if any. Often bad earths can cause a lot of strange issues too.
If that still fails to rectify the issue, check the connection between the solenoid and starter motor. Or any wiring around the battery, anything else that runs from the battery via the ignition switch. (I.e. Alarms etc...)
It sounds likely that you've got a short to earth, a bad earth, or some major resistance on one of your leads going somewhere?
Electrical issues can be the hardest buggers to trace, but I often find the simplest solution is usually the right one. Earth problems normally...