2006 BMW F650GS Oil Tank Leak
Updated: Jul 1, 2020
Purchased in Spring 2018 with 13k on it. Good condition, but had an oil leak, which I dug into right away.
Oil Tank Leak:
Noticed a slight oil leak on the left side on the engine, but wasn't super concerned. Cleaned it all off and drive for a while and it came back once warm. Took the side cover off and it appears to be coming from the oil tank. Cleaned it all up and ran it in the garage looking for a leak... Nothing.
So I put it all back together but sure enough after a bit of riding I noticed it again. This time I pull the cover off while the engine is hot still and run it. You can see oil seeping out a crack on the top of the oil tank...
So took it all apart and cleaned all the oil off the bike. As for the oil tank, De-greased it, Acetone it, Sand it, Acetone it again, then added the JB Weld to seal up the crack.
Something I noticed too, and would really recommend checking out is the air box. I had a good amount of oil in the air box, most likely from overfilling and the oil leak:
While I was in there I was told to check out the valve clearance, although I didn't expect it to be bad at 13000 miles, it was worth checking. You can read up on the valve clearance check process here.
UPDATE: I did not test the fix for a long duration, during this process I was able to source a used oil tank and installed that one. Although the JB Weld fix held initially, I was unable to test it long term to see if it would hold up.