Oil from cylinder ?

I changed my exahaust pipe today bolted in one side of the gasket and used a stud for the other side. To make it easier to fit as i have a zip and its quite cramped we lifted the bike up on the back wheel. It was probably up for about 5 10 mins. I then noiced after switching it on black fluid coming out of they cylinder. What is this ? Is it a bad thing and what do i need to do now ? thanks

 

well the only thing that could come out of you cylinder is petrol as your bike is ac , so as log the bike starts your safe

 

Ok thanks, ive also been told i might need to tighten the bolts up a bit or change jet as i might be running rich.

 

Unburnt fuel