Boy does it get complicated when you are dealing with 70 year old bikes
Please correct me if I am wrong
It seems pistons changed in 1948 (later marks) from high dome pistons with 60.8mm x 4 mm wide oil scraper rings to flat top pistons with 3/32” wide scraper rings.
The original pistons from the engine (seized and buggered) have 4mm wide rings (they gap at 1/16” in the new bores).
My new pistons are a mistery, they have 1/8” (3.2mm). Oil scraper rings.
I cannot source 1/8 wide rings anywhere but could get 2 made at great expense.
Could anyone suggest where I could get a pair, 4mm x 60.8 STD would suit and I will machine out the ring groove.
