Today, I anticipated that 'sweet spot' when the temperature would climb above 25 - but the rain hadn't begun. I pushed the gorgeous T100 (now that I have the original red fuel tank's leaks stopped and freshly mounted it back on the bike) on to the driveway in preparation for a bit of a ride. By the time I got my helmet on, it was raining - I took off anyway.
After finally having the much-loved tank (that the entire project was conceptualized around) re-mounted, and the mysterious 3rd and 4th gear misfire solved (right exhaust tappet too tight) I thought I'd look a little deeper into the 'one remaining problem' (he's an optimist!).
The PO had moved the oil fill spout forward on the oil tank. That it is no longer on top of the tank suits me, as my seat does not pivot on hinges and having the spout in a location where the seat can stay put for fill ups is great. But... there's leak.
The return line from the oil pump has a hole in it, right behind the new location of the opening in the filler spout. At idle, oil just dribbles out that hole, into the tank. At speed, I believe oil is shooting as a stream directly at the cap of my oil tank and when I get back from a ride, there is a smear of oil running down the outside of the tank from under the cap all the way down to making a puddle on the ground. I once covered the filler neck with a square of inner-tube rubber and hose-clamped it tightly on the tank neck and after a long ride, there was zero oil on the outside of the tank, so i know that's where the oil is coming from.
I've tried newer and older caps, with different materials (cork and o-rings) as gaskets, but they didn't stop the flow.