what could i do to clean or flush out the bottom end? when i took my topend off and sent it to wildcard the engine was kind of dirty and before when i had it rebuilt the previous piston had a whole in it the top exhaust side. tiny lil fragments in the oil. the mechainc i had do the work gave me back the piston and said he had flushed it out but i think not so well. any ideas would be great. thanks