Don't laugh at this, but my 741B Indian has been bored out to take 1937 Royal Enfield sidevalve 350cc single cylinder pistons, I got the last two in the UK, genuine Hepolite "Heplex" pistons, +.20".
Where on earth do I get new rings? I tried everywhere, then had a brainwave. The old British Royal Enfield Bullet motorcycles are now built in India, strangely enough, & knowing Indians, they don't change much unless they have to.
I had kept the original boxes my pistons came in & had the part number & size, they were 2.75" +.020, so I got on line & found that the OHV Enfield Bullets they build now are also 2.75" bore, so I ordered 2 sets of +20" rings now fitted to modern Bullets, guessing that the rings used in 2012 would be the same thickness as the ones they used in 1937. At £10 for 2 full sets, including postage, it didn't matter too much if they didn't fit.
Just over 2 weeks later they arrived. The customs form said they were "gifts" & at £10 a pair they were. They arrived wrapped in newspaper, & came from "The India Piston Ring Company", a huge company. My guess was right, the dimensions were identical to my 1937 rings & the quality seemed good, so I ordered 2 more sets as spares.
The "India Piston Ring Company" have a huge catalogue, so they might be worth a try.
