On my 13th birthday, in 1962, I bought a '55 Matchless G80CS 500cc single for $300 hard-earned cash (my farmer parents were very indulgent/naive).  I absolutely loved that bike despite its being broken down most of the time.  Over the years I have been fortunate to be able to recreate some of my favorite mechanical memories from my youth - a hotrod '32 Ford roadster and more recently a super rare hemi-powered '57 Dodge convertible to replace the one I traded the Matchless for in 1966 and then sold for $100.  I frequently considered getting another Matchless, but memories of its shortcomings kept me from doing so.  At one point I test-rode a Suzuki S40 but was disappointed in its performance.  Then recently I discovered 2 things - this forum and Rycamotors.com.  I saw what others were doing with these little gems and decided to see if I could sort of clone my old Matchless.
I started by picking up a very nice 5,000 mile 2013 bike for only $2,000.  I then got a few Ryca parts - air filter, handle bars, megaphone, chain conversion kit, Lucas-type taillight, fork boots - and of course the carb jets from Lancer and timing chain adjuster fix from Verslagen.  Then I picked up Italian alloy fenders, and repro Matchless fender stays from England. I hand fabricated lower fork mounts for the front fender stays, the upper front fender mount, rear fender mounts, and most difficult of all, moved the front mounted foot rests and controls to a rear position.  I was actually able to use the left side including the side stand with no change to the shifter linkage.  The right side required a lot of modification to the brake pedal and relocation of the brake light switch.
Future changes may include a Matchless gas tank and seat.  I plan to put "flying M" badging on it just to confuse folks.
I'm curious to see what readers on this site think.  I've tried to include photos but not sure I am doing that right.

One more - lower fork fender brackets, made with hand tools only.

Left side: