thanks bro for helping but i am now thinking that may be my mechcanic was fooling me because my dad said to me when ever this time of problems occur first we should check the piston rings because according to my father this had happned 2 times in past with this scooter and after the replacement of worn out piston rings with new ones the problem was resolved and i had checked on net as well ,many people reported that this kind of problem was resolved after the replacment of piston rings and their speedo hitted almost more than 50k .ANYWAYS now the scooter had hitted around 37k on speedo because it is only used in city .My father(he had an an experience of about 27 years of scooting on bajajs and similar ones) had said to me that when he will be free from his work he would ask the mechanic about this issue.You know these mechanics use to charge a heavy amount for non essential things from the youngsters like me as I have only a little knowledge about the engine but for uncles like my dad he charges a reasonable fair amount. Thank god I am saved .SO NO PISTON REBORING OR REPLACEMENT

@MODS:PLEASE MOVE THIS THREAD TO Thumpers, Two Stroke And Exotics.THANKS