thanks for the comments, i'd seen the breather on the parts liting but didn't know if it had moving parts which could stick. thinking about it there might be a float which opens when tank is emptying leting air flow in to replace fuel and gradually closes as you fill tank. i wonder if that float is stuck in the closed or partially closed position ? Bike is under warranty and when I phoned Duc Leeds they hadnt seen this problem before. they promised to phone DucUK and 10 minutes later they called back and told me someone from Duc uk was visiting tomorrow and they'ed speak to them about it. Bike goes in Friday for new clocks ( misting problem) and they might look at it then. I'm loathe to strip the breather myself whilst under warranty. be interested to get the breather pages if you can scan them.
Sorry to hear about your problem, guess its best to put it together yourself then you know its done right, it shouldnt happen if you pay to get job done, name and shame the painter
