for sp , change Engine oil & spark plug every 2500km or
every 1 1/2 month , do full service every 4 or 5 months ,
full-service - change engine oil , spark plug , wash carb , wash
piston head , wash block , change coolant , and decarbonise .
also its a good pratices to use good 2t , my sp only use $20+ 2t ,
motul
as for engine oil i only use castrol r4 - $20 , or motul engine