At first I thought this was an Indian Scout, but I realised that the headlight shape was wrong and the engine fills up the space under the tank more than on the Scout. It has to be an Indian Chief. I don't think we can see enough details to be exactly sure of the date but it is somewhere between 1933 and 1937. http://www.indianmotocycle.co.uk/bikes/35chief.jpg http://www.indianmotocycle.co.uk/scouts.html
It's definitely a 1937 Indian Chief. 37 is the first year for tank gear shift ! in 1938 they reversed the position of the headlight and horn plus hid the speedo under a nice dash cover so this must be a 37.