Yeah its only coming out of the tail end of the exhaust. my mix i used was 20:1 6.4 ounces per gallonWe're assuming that the black gooey stuff is coming from the outlet of the muffler and not around the flange where it attaches to the cylinder. The kit exhaust gaskets aren't the best and the flange on the pipe is usually warped from the welding process and needs to be lapped flat so it meets the mating surface of the cylinder.
Either way Xseler's advice is correct. All kit instructions will tell you to run a 16:1 fuel/oil mix. That is too much oil and will result in the problem you've described as well as foulded spark plugs and clogged exhaust systems and overall poor performance.
Tom
Many of us would still say you're a little oil heavy even at 20:1. You can safely reduce that to 24 or even 32:1.
You also need to consider that this is a new engine that is far from being broken-in. The piston rings haven't seated yet and you're going to experience some blow-by around them and the cylinder walls until you get some miles on the engine. We typically recommend 200 to 300 miles before we consider an engine to be broken in.
Break in procedures are as varied as the members here so don't ask what is the best way. It only starts arguments. Type 'break in procedures' into the search box and you'll have lots to read on the subject. You'll need to decide what works best for you.
I will ask what oil you're using. This too can be an inflammatory subject but it is something we'd like to know. Some oils work better than others but again, there are many opinions on this issue.
Tom
Nah just says multi ration i leaned the oil ratio out. Not spitting oil out yet. so far so goodThat's probably okay.
Does the container say what ratio they recommend? Do they offer high and low mix ratios? EX: 20:1 - 50:1? Some oils will tell you to follow the engine manufacture's recommendations and some have their own.
Tom