I have to top up my battery all the time. This makes my think that the battery gets a too high a voltage from the regulator.
Is it possible to adjust the regulator or do I have to replace the thing?
Where is the regulator anyway?
Reg is not adjustable You need to check the voltage at the battery with a volt meter. At idle it should read around 12.6 - 13 volts at 5K it should read aprox 14 usually if you have to constantly add water it is over charging the battery. I would clean all wiring connections related to the stator and the reg/rect Make sure that the grounds are clean If that doesn't help You will most likley have to replace the reg/rect
Check http://electrexusa.com for complete info to trouble shoot your charging system