When a water pump starts making noise it is because the bearing is failing.
When the bearing starts to fail the shaft wobbles a lot.
When the shaft wobbles a lot the seal fails and the pump starts leaking water. On a car, this usually leaks out onto the ground, but on a bike it could leak into the transmission/engine case.
When the seal starts leaking the bearing gets wet, which doesn't improve its operation at all.
At this point it becomes a race to see if you run out of water and overheat first or if the bearing totally fails and something breaks in an expensive manner. If you are replacing water in the radiator a lot then you are hedging the bet some, and not in a good way.
If it was me, I would buy a new water pump and fix it before any of that happened. If it still makes the noise after you replace the pump, well, then that wasn't it, but at least you will have eliminated one easy to fix possibility.
Rod