Typically single layer borewelder pass will build up your bore diameter approximately .250" -  After initial rough cut pass (machining peaks of the welds down to the valley depth) usable buildup is approximately .180". If you measure your bore prior to welding and the difference between your desired finish diameter and current un-welded diameter is .180" or less, one weld pass will yield enough material. If difference is more than .180", you should plan on a second weld pass.  Typically no cleanup other than quickly wire-brushing the soot off of the first weld pass is needed to apply the second boreweld pass.