If you are of a nervous disposition, sit down and take a tranquilliser before reading any further, right, feeling relaxed and comfortable, good.
I had really big problems getting a gas tight seal between the exhaust pipe and the cylinder head on my D Comet Replica, I used every method described above, but all to no avail, after a short period of time the exhaust nut was always loose and leaking, and loud! horses did not like it all.
In desperation I found on the internet some solid copper washers with a perfect I.D. and slightly oversize O.D. that was easily remedied with a fine file, a bit laborious, but easily doable, the washer by the way is 0.0723 thou thick.
Obviously the copper is a relatively non compliant material, so once the exhaust nut is tight it sets the position of the exhaust pipe fixing bracket and the silencer, and this is where I found my problem to be, bearing in mind this is a replica and not a factory creation, as we know there is really only one genuine D Comet that we are aware of.
So with the exhaust pipe fitted tight into the cylinder head using a solid copper washer, and the rear of the exhaust pipe attached to the footrest plate (I think, I am to lazy to drag the bike out of the garage to check) where does the silencer end up, well actually in a pretty good position, nice and neat looking, just where it should be.
Well that is until I try lift up my D stand, and it fouls quite badly on my silencer, and will not retract any further, well I pondered long and hard over this problem, and I am sure there is a really good engineering solution out there, but unfortunately I am not an engineer, so I looked at my available stash of used silencers, and found one of the early Club spiral baffle silencers, the ones that were supposed to offer a really nice sound without sacrificing performance, very important for a Comet apparently, this silencer had some slight chrome and surface damage on it, acquired when "Olive" decided to pull right across my path when I was travelling reasonably quickly, not nice, it was one of those somersault over the car accidents that can end in total paralysis, thankfully not on that day!
Anyway I looked at the slightly damaged silencer, and thought to myself "what harm can it do" this is where the tranquillisers come in handy, after making some rough marks on the silencer with a permanent marker pen, I set to with fairly heavy ball peen hammer, periodically checking my progress, the offending part of the stand was where the additional reinforcing strap is situated at the top of the R.H. stand leg, eventually I got the indent pretty much feeler gauge perfect, and not even the 25 thou one!
So far, so good, I have done a good few miles, the exhaust pipe always feels tight in the cylinder head, mind you, the horses still don't like it, but then again, should such beautiful animals really be sat on by human beings, let alone being made to carry them along tarmac roads, but thats another subject entirely.
