Cheers Trev , the bike's an EFI. I came across the breather from the tank and it comes out down around the centre stand and is cable tied on loosely , on one inspection the end of the pipe was sitting squarely on the main pivot housing of the stand , so I moved it , but maybe I need to re-locate it and fix it more securely . I also removed the fuel cap today but didn't really hear any vacuum . Will have another look tomorrow and go out for another local ride . Thanks for your input.