Should i also change the impeller? Of do i need to buy this full list of OEM parts?
You'll need all those parts plus a stamped impeller if your pump has a cast impeller. Put your bike's year in your profile and whether it's a C, T, S, or RT. Changes occur in parts throughout the years. Is oil coming in drips from the pump's weep hole?
As thecableguy has observed, white smoke indicates that the head gasket might be leaking, especially if it keeps occurring after the engine is warmed up. You might be able to observe bubbles in the coolant reservoir. Those would be caused by a head gasket leak. You should determine this first before laying out cash for pump parts.
