Battery?

[BobAin'tStoppin']

Try this, Put your voltmeter on the battery terminals (not the wires leaving the battery, but the terminals themselves). Then try to start the bike and see what happens to the voltage. If it drops below say 9 volts the battery is either bad, or in your case, perhaps just too small for the application. In my limited experience the BMW bike charging systems are very reliable, so my guess is either bad connection or bad battery.