Had enough of waiting for some sunshine, so went off to the garage to have a poke about. Kwaka silencers are a bit tatty and the downpipe on one side was a bit loose in the head, so off they came (carefully as I didn't want a sheared stud in the head to deal with).
Discovered that some idjut had reused the gasket a few times, so it came to pieces as I removed the finned flange and collets (more on order). This may also go some way to explaining why one of the domed nuts had lost it's dome (possibly by tightening beyond its depth?). Anyhow, 10 gaskets = £13 and 4 dome nuts = £3.79 - originals had a flange but a washer will be fine. Next, I'm going to clean up the pipes and cases with a dremel type attachment, and clean up the places I can't usually get to with the pipes on.
Question - what are the opinions on 'silencer' types. Many say as long as they're not marked 'not for road use' or 'not for speed testing', they're ok. Mine have something mentioning 1985, which is a key date for some kind of legislation, and they're like a medium length megaphone type. You can't see straight through them, so have some kind of noise dampening arrangement. I'm not too bothered, I think plod have better things to do and, if the HDs can get away with their racket, I don't think I'll have too many issues.