Just to add that the watery black leak on the exhaust where the stinger joins the end can is indeed just petrol and 2 stroke. It wants a fresh gasket in the joint and she'll be sweet as. My exhausts leak (the same watery black stuff) where they meet the cylinders and i've not been able to reliably seal the joints yet but it isnt hurting anything - i just leave a sheet of cardboard under the bike to catch the drips.

Mine aren't standard exhausts by the way, the exhausts on a standard bike won't leak if all the exhaust gaskets are good.
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After years of moaning about immigrants now i am one...