I took my '69 Thunderbolt out for a long ride this weekend. I hooked up with some AMCA members for a ride. Went with a 79 Guzzi, a 61 Panhead, a Knucklehead rat bike, and an awesome CBX. I rode about 120 Miles on Fri. Stayed with my son, Rode probably 100-120 miles on the ride, and another 120 Sunday to get home. Say 360 total miles.
I left the house with a full tank of oil. Toward the end of the ride I checked and oil was at the L mark. Hmmm. I bought a gallon, added a couple quarts, and strapped the rest to the bike. Upon returning Sunday checked and it was back on the L mark. So I lost about a gallon of oil. Where did it go?
I looked up a thread from Jan '14
Regarding the breather: On the second attempt at joining the cases the camshaft was in a bind. The third attempt I was careful to line up the cam and the breather disk and made sure the cam rotated freely. Still.
I don't think it is burning it. That much oil through the engine would be billowing clouds of smoke. And there are none. Plugs look pretty good, a bit sooty but it runs rich at idle. Exhaust tips are sooty but not greasy.
When I park there are no puddles, a drip or two, that's it. One would think it would be dripping everywhere, but it 's not.
Today I pulled the primary cover and there is definitely oil in the primary, but not much. So there is a crank oil seal issue there, at least.
I drained the sump. This is all the oil from both primary and sump.
I don't know if this picture will show it, but there is evidence of oil on the right side muffler. Left much cleaner, but not spotless, there are a few streaks on the top.
The only thing I have found so far, was the bolt that secures the oil return manifold to the case was a bit loose. I found that Sunday morning and tightened it. And still lost two quarts on the 120 mile ride home.
Where does a gallon of oil go, without leaving much trace?
Somewhere between running, and running well, I suppose.
I finally got around to better background than my junky garage. Here are a few pics.