A bit long winded but I Just bought a 2008 990 adventure that was faultless on the test drive from a private sale. Rode the bike home approx 8 miles no problems on the reserve light. A couple of days later I went out for a proper ride, popped to the garage and put 5 litres in each tank, 20-30 minutes later the bike started popping and losing power, could only use a quarter or a third of the throttle, any more than that and the bike was not responding. I limped the bike towards home and stopped at a garage and thought I would top it up with fuel to see if it made any difference... turned bike off and opened both fuel caps but noticed the garage had just closed, started the bike and low and behold it was running normally again as if nothing had happened ?? I thought straight away ‘air lock’ ? I had the left side tank off Today and the top front vent hose is missing, the mid way hose goes down past the clutch slave cylinder, the other top vent hose goes across the frame to the other fuel tank on the right hand side... I can’t figure out where the missing hose would go ?? Does it Hang straight down The tank or Does it go over to the right hand tank. I’ve not taken the other tank off yet but I’m guessing the top front hose will be missing too. I’ve taken the fuel pump out... looks like it’s never been out before for a filter change and the bike has done 18.5k miles Before I took the left tank off I filled the bike right up and rode a good 2 hours with no issues ??? I am hoping it’s just something simple like a pinched vent hose that caused the problem but I do need to know where that missing hose goes. Any help would be much appreciated on possible reasons why it may have done this. Cheers Rusty.