What battery? What problems does it have? Is the problem with your actual cells, or is it a problme with the BMS? Or is it a problem outside the battery, with the bike itself?
If it's a proprietary bike that requires that specific BMS (the usual reason for keeping a specific one) then the BMS may not be transferable without specific procedures to ensure no connections are ever left wthout power. Some may be more complicated, or less, but I don't know the procedures for any of them myself (there are threads for some if you look around).
Also, some propietary BMS will brick themselves if any cells ever dropped below some critical level, and refuse to charge. Replacing the cells won't fix it; unless the factory can reset it the BMS is usually toast in these cases.