nothing major, only 2 possibilities with this problem.
1) battery terminal are loose, if u are using maintenance free battery with wire attached with horn clips to battery terminals than better get those terminal soldered with good quality wire and than join the those wires with bike own battery terminal wires.
2) plug coil terminals underneath the fuel tank are loose and they do get loose as they are attached with horn clips with the coil.
so ask any electrician do make them fast and secure them thin copper wire and masked them with electric tape. this way they will not get loose.
i went through same problem and after doing above mention measures problem never occur back.
use some time the mixture of hi octane with normal fuel as fuel we are getting is of real poor quality.
oil grade is fine. summer approaching so use any good kind gasoline engine oil of 20w50. local oil do the same job in less price compare to any fancy name imported oil.choice is yours.