I have a 750w RW Bafang motor making a click noise on the disk brake side. Seems to only do it with weight on the bike and slightly more during a left hand turn or sway. Tic tic tic. I'm thinking it may be a ball bearing or brake shoe is doing it. I keep everything very clean but I'm wondering if a piece of sand may have gotten into the bearing race. Are these sealed well and so they need to be disassembled cleaned and greased or tightened or what? Are there any bearing kits available? I prefer Japanese or Swiss bearings over Chinese. I have had a lot of experience with other machinery and bearings but have just never torn down a hub motor before. Thanks!