Thanks Gadge, that picture is a lot clearer than the grease smudged photocopy I'm looking at. It makes sense too, given the shape of the baffling inside under the cowl. I did a bit of a 'road test' earlier, and I reckon I'll have to cut the vane down a fair bit. Or possibly get a stronger spring. It's okay at idle, but 'hunts' badly when the revs are brought up. I'll work on it some more....