no that sounds like an airleak, theres is a possiblility that you are jetted to lean.
what are all the mods you have done?
what size jets are you running?
what are you premixing it at? should be 32 to 1, 4 oz to a gal. ect.
mine spits some oil as long as its not smoking like a mofo you should be alright..
pull your plug and do a search on jetting..
i put a filter right on my carb and i had to go from a 230 main up to a 260 as of now plugs like a dark brown long as its not white/lean black/richthatd be the best thing check your plug color like he said go from there. thats a good quote 305 like chris rock said if each bullet cost $5000 thered be no more innocent bystanders lol
No, It will just get water and debris in your flywheel and stator. There is a crank seal preventing air to enter the cylinder. Your running too lean. There is either an air leak or your jetted way too lean. Get the bike to idle with your choke, then spray some carb cleaner around your head gasket and base gasket. Check all around the carb as well. See if your idle changes while spraying.