Jump it off your nearest car battery. They are both still 12 volts and only different in amp capacity. Physical size of the battery will not it hurt your smaller motorcycle battery. If you could mount a car battery on the bike it would work just fine. I like to hook it up to the ground connection point on the frame (above the battery and to the right side of the frame). Then hook your positive on the solenoid on the wire that is bolted to the battery (which should be the red wire on the right side of the solenoid - the black wire on the solenoid is the starter wire which would work too but will engage the starter without hitting the button plus it bypasses any safeties and would be bad if it's still in gear).
Sean