Erik,
I've gone through the Spare Parts Catalogs (SPC) and tried to categorize the different chain tensioners through the years/models, as presented by the SPCs.
- primary-chain-tensioner.jpg (54.86 KiB) Viewed 13083 times
The SPCs don't always tell the whole story. For some reason I thought the early (pre-1958) tensioners were made of Stellite, a really hard steel alloy.
Then in 1958, with the introduction of the XLCH, the tensioners changed to a plastic material, with a plain steel substrate. The XL/XLHs retained the two-part bracket system, while the XLCH used a one-part bracket system. Both had some modifications over the years.
Help us out here. What really happened with Harley-Davidson's production of chain tensioners? My value-added to this website is digging through 60-year-old factory documentation. Unfortunately, that comes with scant factual knowledge. So, as Blanche DuBois said, "Whoever you are, I have always depended on the kindness of strangers" to explain the intricacies of the Ks and early XLs.
Dave