On my Buell XB12 and Honda XR I use these: http://www.ebay.com/itm/X-Grip-Motor...YAAOSwa-dWoD7K

They work great and since I use the phone (iphone 7) for navigation which sucks power the USB charger keeps it topped off. I have a spare one of those holders in the box but after allot of test fitting I just haven't found a good place to mount it. What cell phone mount solutions have you tried?