Ill jump in here and feel free to tell me to butt out....
But first of all it would be helpful to know which year and model as they differ. My understanding is early rigids and plungers had a flat(ish) lid and more triangular,, swing arms are more rounded and a slightly curved lid. I have several for various projects (Singles and twins)... and on some non stock bikes ill adapt a Enfield one as they are super cheap on Feebay or some dealers.
I can snap some pix of some of mine for reference if you like but I am not selling any at this time,,
But my $0.02 on repops,, the asian & indian made ones vary tremendously. I know some of the people in India and my close friend Sobby is a manufacturer. He correctly and wisely advises that most of the sellers are agents and the people who make the parts never hear from the consumers. They would happily correct issues if known in most cases but its a communication issue. In Sobbys case. He IS the manufacturer and warrantees his products for life against my strong objections and advice. ( a limited time span sure,, but lifetime is a long time).
Many parts like that I call 90% parts. They get it right most of the time,, but its always some little thing.. If you could just get them to correct those issues it would transform the business.
As to repair,., theres several ways to do it. I worked for years in aerospace and know some of the top welders in the world. Amazing stuff. They can weld paper thin materials with zero distortion and defects. I used to have in my tool box 2 safety razor blades welded end to end on the sharpened edges with a perfect weld bead. ZERO distortion. The key is Tungsten Inert Gas welders with good heat control and gas shielding. At a foundry-manufacturer I worked at for 6 years I call "Pretty Close Cast parts" we had some really nice weld chambers.. From small weld boxs with gas ported in to full chambers that looked like sandblast cabinets. You slide the part in, seal the door, a pump draws out the Oxygen and then purges the chamber with argon, Argon/Nitrogen or in some cases a Argon Helium or other gases mix.. You can weld all day in a O2 free environment without traditional issues.
You can also make purge shield plates out of perforated copper and apply to the backside and with careful weld control weld with impunity.
Another method is metal spraying. Several vendors in my area will clean sheetmetal or your cars 1/4 panels,, then use a liquefied metal spray and rebuild the area up.., It works great for rusted out and paper thin areas. Will never rust again either. I have 30 years experience doing custom body and paint, and many ways to solve these issues...
One thing I used to do frequently is take a angle finder and contour gauges and make templates for needed patch panels. Go to the wrecking yards and find a car with similar curves,, cut out an area much larger with the nervous saw. (I use a DeWalt cordless saw, drills and angle grinder with cutting discs while mobile) Take it back to the workshop and tack it in place,, I an okay welder but on precision stuff take it to one of my guys and pay to have it finished welded in. Then I grind the welds down, shape it, Anneal it if needed, and paint the sucker. There ARE people out there who can do this if you cant, the question is time and money.
