| I agree that jump-starting with a (running or non-running) larger capacity automobile battery won’t harm your Ducati. It’s indifferent to the source of 12 volts supplied to its terminals. The only difference is the ability of a larger capacity battery to deliver a higher current and longer durations, i.e. repeated starting attempts.
I suppose if you left the cables connected for a long period of time after you started the bike, you could encounter higher regulator temperatures, but as a practical matter this isn’t a concern.
I don’t know the exact specs on the Ducati starter motor, but in general, motorcycle-size starter motors draw around 30 amps under no load (max rpm) and around 85 amps under typical starting torque loads for unmodified motors. However, this figure can briefly rise to 300 amps under a stall condition typical of the initial start requirements of a high compression motor.
If you look at the wiring running to the starter motor you’ll see that Ducati made a trade-off between cost and weight vs. electrical resistance. The higher the resistance, the lower the current that is delivered to the starter motor and the more electrical heating of the wiring. The lower the current delivered, the harder it will start.
Sizing the battery and starter cables for at least 100 amps seems more reasonable to me. A number of 996R owners have reported easier starting after they replaced these wires with a larger gauge.
But before you replace any wiring, first check the circuit for points of high resistance, Corrosion at the connection to the starter motor is the prime suspect because water often collects in the rubber boot covering the connection. Clean the connection anyway and then fill the boot with dielectric grease to keep the water out.
When a battery nears the end of its life, often the voltage across its terminals will measure 12 volts or so, but it can’t deliver sufficient current to turn the starter motor so all that you get is a solenoid click.
Finally, the technique to connect jumper cables needs clarification.
The last connection that you make will generate a spark. This connection can be made to the chassis (earth) of EITHER vehicle but only at a location physically distant from the hydrogen gas contained in both batteries.  |