The K75 clock uses a PCF1171 clock module, which draws 400 uA typically. That's not enough to drain your battery in the time you specified. Other sources of problems could be failed diodes in the alternator rectifier circuit, and on ABS equipped bikes there is a relay which when fails, drains the battery.
To test for a parasitic drain, you need to insert a resistor shunt into the ground cable and measure any voltage drop across it. Here's the process:
1. Purchase two 2 Ohm 1% 1Watt precision resistors from a reputable online electronics house like
Digikey or
Mouser. Connect them in parallel.
2. Remove all fuses and make sure the ignition is off
3. insert the resistor pair between the ground wire from the negative terminal of the battery and the grounding point on the transmission.
4. Attach a voltmeter across the resistor pair and set the scale to 1V, if available. The voltage you read will be equivalent to the parasitic current. For example, a parasitic current of 1A will indicate 1V; a current of 100mA will indicate 0.1V (100 mV) and so on.
5. Note the voltmeter reading with all the fuses out and the ignition off. It should be zero or near zero.
6. Insert each fuse and read the voltage. If no change in reading, then remove the fuse and insert the next one.
7. Eventually, if you have a problem, the voltmeter will indicate a non-zero reading. Now you know which circuit on the bike is the culprit. You have narrowed your search. Diagnose the circuit.
At no time, should you turn on the ignition or try to start the bike. This will blow apart the resistor shunt with the current draw.