I bet you any money the previous owner hadn't quite sussed out the oil level/filling technique and overfilled it. It is very easy to overfill if you aren't careful. Any excess will quickly blow through the crankcase breather and accumulate in the airbox (and that's your air filter leak). Also if not filled carefully oil will more often than not spill out the filler hole in the frame and trickles down and accumulates on and around the radiator and takes days if not weeks to slowly trickle through the fins (and that explains the oil coming from your radiator). In fact its not uncommon for dealers to make a mess of oil filling changes!

In a nutshell, don't worry about it. Drain the airbox out of its drain tube, check the airfilter isn't contaminated, check and clean round the radiator's left hand side and recheck the oil level carefully as per handbook/manual. Basically the bike should be level with engine having run for a good few minutes.

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