You may be questioned about your intention to travel on B1/B2 at the port of entry immigration. You need valid documents, and proof to support your intention to travel on B1 in order to enter the country. Even if you say tourism, you will have to produce itinerary, funds for travel, address of stay etc.
It is always in good sense, to move to a different company in India who is willing to transfer your H1B into theirs and send you here. You dont want to be asked on your next visa/ immigration interview, as to why did you enter on B1 and then get transferred into H1, when the purpose you mentioned on B1 entry was tourism and that you would return back in 6 months or less.