i bought a 1972 honda sl 125 off of my dads friend for 50$ it was so cheap becaise the whole wiring system was messed up we got it fixed at a shop and when we got it back the person who fixed it said that it needed a new carborator so we had to run it with the choke a few weeks after riding it, it stared to maked a clacking noise in the motor ansd i couldnt give it throttle what i want to know is what you guys think could of happened we took the top end off and saw nicks all over the piston and all over inside the head my dad trhinks something in the valve broke what do you think?