I have a 2009 Ktm 990. I have purchase a water pump rebuilt from Rottweiler. From videos,etc I have watched I need a case gasket to replace once it has been removed. Does any know this not to be the case? Can the water pump rebuild be done w/o removing side case? And I haven’t been able to find just this single gasket for sale, it has just been in a multiple gasket kit $$$$