i know of people who say that it can take months to get the full power of the brake working,at the moment my 203mm front bb7 on my simtra is working like a beast,put i have had it a fairwhile now,maybe 6months ;on my inspired my bb7 160mm is bedding in now,the first week or so lacked any bit or hold but recently it has been getting better and better.
so i say give it time and let it bed in.