Brown gunk leaking from carb

[gixersix]

It's probably the residue of ethanol attack of your carb seals. It was previously obvious on my No1 carb, before BSD changed all my carb seals ( internal and external - which were all fucked) and reset the carbs - which had been over-adjusted by a German Yam dealer, to compensate for the variable fuelling. (i'd ended up with a litre of unburnt fuel in my engine.) This problem will be getting worse now as the Gen1 bikes get older because ethanol content is rising.