Check the big wires for loose connections
Yup the ground loosens up and the big wire on the starter will do it too, then it does nothing but click and get hot. I have had to address both issues multiple times on my assortment of bikes. If you have an OEM ground wire that connects to the speedo cable retainer bolt you might give some thought to getting a longer ground cable made and running it down to the transmission mounting bolt on the bottom right side.
Remember the K.I.S. method. Keep It Simple