nice info yamaha135...bus awam ko thora easy language mai samjhaya karo.....inni technical to mujhe bhi 2 dafa perhni pari 
@ imran bhai...
bhai dekho piston jo hotay hain unki surface to specially treat kia jata hai to endure more stress...(heat treatments)..
jab apnay upar se katwaya to uska heat treated layer bhi chali gayi.....jis ki waja se piston heat ho ker sieze ho gaya