Retitling this post...

Hi Paul, 
I was a bit like you when I got my Norton many years ago, finding odd bits loose after a ride and reinforcing the stereotype of brit bikes vibrating themselves to bits.
What worked for me was to go over the bike every time I used it and checked everything. 
After a few rides I began to find out what did work loose and what didn't. The bits that didn't would get the loctite treatment.
The obvious exceptions being the exhaust nuts into the head and the cylinder head. These were retorqued as required - the exhaust nuts when hot. Nowadays my Norton is 99% OK to just get on and ride without worrying.
I should also add that I tend to keep the revs 'sensible' in that I rarely use more than 5000rpm for very long. (4000 is about 70 in top for my bike)
Hope this helps,
George 

Never had the exhaust rose's work loose after tightening up when hot and drilling holes to wire up. 

Perhaps it's the paint on the faces crushing down?  I've never had an exhaust hanger come loose, but Norton actually advised new owners to tighten them when hot because the new enamel softened.

Anything on an old bike can vibrate loose or just break.

When it happens, you make sure it doesn't happen again to a particular fastener, seeing as how the factory didn't bother.

You use locknuts, self-locking nuts, Loctite, drilling for wire or springs, rubber mounting...

Have I missed anything out?

the brackets are often a strip of metal with two holes, fitted at an angle from frame to silencer: this is therefore untriangulated and highly likely to try and move out of position, let alone come loose. Design needs correcting first. Exhaust nuts: changing to material which expands with head temp. is a big help.

One item on my Wideline Dominators which routinely come loose are the wing nuts which hold the seat in place. I would not recommend locktiting them, as you may not get them undone again; ask me how I know! I've tried putting a spring washer under them, didn't work, shakeproof washers likewise. I am now in the habit of regularly checking them whilst riding along; not ideal; and of course before and after any ride. I have lost a few, and they are not so easy to replace.....

As for everything else, I concur with what has already been said, constantly checking and re-tightening is part of the fun of being the custodians of these old machines! Bonding they call it, or, as Phil Irving once said, (getting to) 'know thy beast'!

Ian C.

You should be able to drill the wing nuts and connect them together with a spring.

Bought my first Norton in -66. At first every nut seemed to come loose. A few years later they usually stayed tight. Have found torque needed to keep them in place. I now have some modern bikes where most nuts have torque values in the manuals. Amazingly low torque needed.
If I don't use a torque wrench, I usually overtighten. Hard to recalibrate my hands to modern low vibrating bikes. One of the few Norton bolts that needs mechanical discretion is the fork pinch bolt holding the axle. Not unusual to see cracked fork sliders. In my experience neither spring washers nor Nyloc nuts solve the problem. Loctite often does.

Paul, Your seat retaining clips (Terry type) are peculiar to the 1960 bikes  mostly seen on the DL  paneled bikes built in 59 and sold as 60 models ,some std Dommies also had them . As the seat is a bit insecure and MOT testers could fail them ,they were soon switched to the Dzus fitting . The Springs and frame mounts are availiable from the club . Seats are hens teeth . 

If you wish to make your seat more secure you will have to make a seat tab for the rear of the seat and fix to the seat pan . Then drill tab and  rear enclosure for the Dzus and fix a Dzus mounting under the enclosure. Not an easy job as the enclosure has a seam at this point . Look at other Dommies and you will get the picture . Alternatively you could make a strap to go accross the seat and fix to the bike.  Or just use an aerolastic !.