Your electrical system should never be running for any length of time without some reserve capacity. If it is, you're overloading your bike's electrical system. You should have enough capacity to run your accessories, ignition, and to charge the battery when it is depleted after starting the engine. Eventually, the battery is going to reach a full charge state, and that will represent excess capacity right there.
So the regulator should ALWAYS be dissipating some energy. It really does not take a lot of energy to produce a lot of heat. As an example, I used a pair of 3.3 ohm, 100-watt power resistors in parallel with the turn signal LEDs on my GL1500 to keep the auto cancel operational. When I fed 12 volts through them, they dissipated approximately 43 watts each, and reached a temperature of 180 degrees F in about 30 seconds. I mounted them to the frame of the bike to use as a giant heat sink. That, and the fact that they are on a 50% duty cycle (they're turn signals, so the power is intermittent), was enough to keep the temperature down to a point where they wouldn't melt my trunk/saddlebags.