Hello today i bought a near new 2013 dhz 160 dpro with ten hours on it the chick i got it off said it hasnt been serviced since she got it i rode it for about an hour went okay 1st to 3rd but 4th seemed to bogg out and was blowing alot of white smoke when first started was cold tho, but im gussing it needs a service and i plan to upgrade carby to a 30mm flatside race carby with 1/8 throttle and plan to upgrade to big bore dhz exsaust , but the main issue im worried about is ever time the bike dies or i turn it off all i can hear is some bubbling gurgling noise the chick tryed saying its normal for oil cooled bikes but i wouldnt know always been a 2stroke person tryed googling it cant find nothing on oil cooled bikes and if its normal or not how can i check the oil for the oil cooler?