If your crankcase was overfilled,.. some oil will be blown out the breather into the airbox...
You're doing right... just clean it out, and see what happens from there...
Riding at highway speeds might also throw, and burn, a little oil... but, that is mostly burned...
PS... You can get a washable K/N filter that fits in the stock box... or, there is a DIY oiled foam filter conversion in the Tech section... if you want to save money on filters...
Them stock one's is pricey...

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