You can do it, but you will need a different adapter to mount your caliper in the right position for the larger rotor.
I know you are trying to be economical, but spending money to try to fix up crappy brakes might not be the best investment.
Pricepoint has BB5's for 30 bucks complete, and BB7s for around $50. I think that would be better than spending $25 to add a bigger rotor to a crappy caliper, and give you better results.
The bigger rotor will be a noticeable improvement.
I know you are trying to be economical, but spending money to try to fix up crappy brakes might not be the best investment.
Pricepoint has BB5's for 30 bucks complete, and BB7s for around $50. I think that would be better than spending $25 to add a bigger rotor to a crappy caliper, and give you better results.
The bigger rotor will be a noticeable improvement.