I searched for several different things but none seem to pertain to my issue. So here goes! I have a 2012 YZ450F and I took off the back tire today in order to swap out my old tire for my new tire. After I finished getting the new tire on the rim, I put the tire back on and lined her up and checked my chain tension and all was good. So, i crank her up and take her for a small test ride down the street to check and make sure everything felt ok. When I attempted to apply the rear brake.... nothing! Normally, I can barely tap it and it nearly locks up. So, I press down harder and harder. I nearly have to put my weight on it before it will lock up the rear. What's happened? I didn't touch the brakes other than to move the caliper to the side in order to slide the wheel out. Anyone have a clue what I have done wrong or what's going on. I checked the line to make sure no fluid was leaking just in case... and all is good. I read a post where someone had a similar situation with weak rear brakes but his was after bleeding his brakes. I had no need to, and did not bleed nor brake the seal on the fluids period. So, why would it take soo much force to lock up the rear now? I am pretty sure I had no grease on the rotor because I made sure I wiped it off with a clean cotton rag before I put the wheel back on so surely I didn't compromise the pads by getting grease on them. btw, the pads still look like new. suggestions? cause im lost now!