I fixed the front brake problem - I just needed to crank everything down till it bent the backing plate and then keep going. I even added a battery, a key-switch, and a horn. Now I have a new problem though.
The chain keeps stretching. I put at least a 100 miles on this back with the 6hp engine, and now with the 14hp I have to tighten the chain a half-inch after every mile. I know I've already stretched the chain at least 5 inches, so I'm going to replace it with something higher quality when I do my sprocket-swap.
After too much research I decided on EK's SR heavy duty, which has a tensile rating of 7000+ Should be more than enough.
Edit: Did the math. I should only need 2000 lb/ft or so... buying the EK420SR anyways.