Post some pictures up may give a better clue. Could they be off the filler cap? Don't appear to be from fuel cap or sender unit ! I'll get the Mrs to post a picture of the bits when she gets back from work. Another question, (sorry !), underneath the fuel tank towards the rear of the tank are 2 breather holes to which two rubber pipes are attached. When I removed the pipes I noticed that the metal tube on the left (nearest the petcock) was rusted at the tip - I am able to blow air through the right hand side one and you can hear it exiting near the fuel cap, but, I can't blow air through the one on the left - am I correct in thinking that this should be clear to allow air to travel through ?, and if it is blocked somehow, would this cause fuel "blowback" into the carbs/airbox ?. Long winded question I know but I feel that the vent is there for a reason and should allow air to pass through freely. Thanks so much for your help - the garage is extremely cold at night and I am getting fed up with this bike, which is a pity because when she ran well it was brilliant . . . Mark.