B44R Engine Oil Syphoning Out of Tank

[B44R Victor]

An extraordinary thing happened to my B44R on the way to Bikes at The Manor on Sunday.  Because it was hot and my banjo bolt below the tank was weeping, I topped up the engine oil to a good 3/4 full with Classic 40 XL.  I've read Rupert and have noted "be careful not to overfill".  When I was 10 miles into the journey the engine started to sound rough and dry, like there was no oil in it!  I slowed down, took it steady and just made The Manor.  On checking the oil level, the additional top-up had disappeared with half of what I normally carry.  It was below "Low".  Fortunately Dave had some 20-50 and was good enough to bring the level back up to half way to get me home.  It was a rough ride home and it didn't like the 20-50 but I made it, so thanks Dave.  Today I've done an oil change, put Classic 40 XL back into the tank to half level and guess what?  It's almost back to normal after a short test run.  Did I overfill it and cause it to syphon away?  Has anyone else had this experience I wonder?     

[iansoady]

It must have gone somewhere - either leaked or burnt. Or the return side of the oiling system has failed somehow and all the oil's in the crankcase.

[B44R Victor]

I checked the oil return pipe when I got home and it was trickling in OK.  The 20-50 top-up was still in the tank at a level half way up.  I think as the oil in the tank has expanded as the engines warmed up, it's seeped out of the overflow and created a syphon effect.  Since I've refilled the tank with 40 XL and kept the level just above half the bike seems to be running OK.  So don't overfill those tanks?