A weird thing you can try for your issue. Before hitting the start button turn your key to on, turn on your brights and let them sit for 2 minutes. That draw will warm up your battery and allow the magic bits to hit your starter with a lot more amperage. Be wise about doing this if your battery is old and might drain down first.
I tried your "weird" idea and it worked! I only tried it once though, but will test it a few more times. I left the brights on for just 30sec.
2010 Monster 696, 1981 Yamaha DT175, 1979 Yamaha XT500