my bike recently blew up, the piston clip came out and scratched up the whole bore. so I brought a new one from a wrecker, I brought all new piston and rings and put it all back together. an hour of riding the bike shits itself. I tear it apart and find the piston hit the top of the head and it broke the aluminum mold for the pin on Conrod, I felt pretty lucky since I only have to replace the piston. I Measure the difference in bore length and it's only half a mm. what should I do to make the bore longer, and another base gasket? buy a larger gasket?