I know some folk have had success in cleaning a vap / gen tube, but I haven't. I have occasionally removed the pricker wire and cleaned the carbon deposits off, and knocked some rubbish out of the tube at the same time. But there's no way to get at the very top of the tube. The pics linked in the last post of this discussion show why - http://0flo.com/index.php?threads/7236 Your problem is (as others have suggested) probably a worn jet. Or a blocked tube. Good to hear you've got it running well though.
I am in the process of fettling a 300x which has a dubious vaporiser so i will try it on this lamp just to see how it performs , probably the same but we will see. All a learning curve. Thank's, Clive.