Dear brother aqs,
As for your question:
Is Syedna Mohammed Burhanuddin (tus) Dail Mutlaq and true vicegerent of Imam or not??
Part -I
Please see the front page of a “Dastoorul Amal” (Constitution) for rich and poor Bohras constituted by Namdar Sakhidatar Seth Adamji Peerbhoy Rafiuddin Saheb Sallamullah-o-Ta’allah and made public by then 49th Dai, Syedna wa Molana Mohammed Burhanuddin Saheb Sallamullah-o-Ta’allah, some 125 year ago. 49th Dawoodi Bohra Dai, Syedna Mohammed Burhanuddin Saheb was father of 51st Dai, Syedna Taher Saifuddin Saheb and grand father of present 52nd Dai, Syedna Mohammed Burhanuddin Saheb.
From the cover page of booklet attached here you can very well see that:

1) There is no TUS or Dai-ul-Mutlaq after 49th Dai’s name.
2) There no claim of Dai being vicegerent of Imam in seclusion any where.
3) There is no Abde-Syedna before Seth Adamji’s name.
4) Sallamullah-o-Ta’allah is used both for Dai as well as common Bohra, Seth Adamji.
5) 49th Dai, Syedna Mohammed Burhanuddin Saheb used to stay at Surat in Devdi and Seth Adamji in Bombay in Peerbhoy Palace . So the booklet has ‘Press Line’ of Bombay ’s Al-Bayan Press.
6) Boldest letters are of “Sudhara naa Kaaydaa” – ‘Reformed Customs”, clearly showing that earlier Dais had no allergy or hatred with word “Reform”.
7) The reform was for the Bohras of the areas of Sir Adamji’s influence, Kathiyawad, Jhalawad, Halwad and Sorth.
Reason for the urgency of this reform was the incoming prosperity in the community at the threshold of 20th Centaury and lavish spending by neo-rich Bohras during marriages, majlis, fateha jaman etc on one side and acute poverty and indebtness of their Dai on the other side.
Dais before 51st Dai were so poor and helpless that in 1891 an Amil of 49th Dai, Sheikh Abdul Tyeb tried to put him in Jail for non-payment of his loaned amount of Rs. 50,000 given on simple interest amounting to Rs. 4000 – total Rs. 54000.
(Justice Martin in Chandabhoy Galla had observed that 49th Dai neither excommunicated this audacious Amil nor stopped his vazifa by Jamat and nor punished him. This clearly establishes that there was no concept excommunication or Jamatkharij and it is of recent addition.)