Might take off the front drum (as you know closest to firewall) line from the M/C and take the hard lines off of the hoses at each front frame tab & blow thru em to see if they're clear. Before doing that tho, w the front wheels off the ground & a helper playing w the pedal and you spinning the tires forward by hand do the fronts lock solid from spinning in the air? M/C rear (front brakes) piston/seal might be poor), inadequate psi. Holler back w you can