by hugoct » Mon May 27, 2019 9:04 pm
The KR had two basic front frame sections.
47006-52R (the heavy frame) which was used on KR and KRTT through 1957 and all XLRTTs.
47006-58R (the light frame) which was used on KR and KRTT from 1958 on.
Keep in mind the factory recommended the use of a Sportster frame, forks and shocks if you were going to be racing on the beach at Daytona.
Both frames use the same castings from 1958 on so that is no help.
There are multiple changes to the frames starting in 1953 with the last change in 1970.
You have to weigh the frames and hope someone hasn't cut and ground off a bunch of weight.
Please post pictures of the frames you have with the steering head casting number or steering head welded area and the seat mount date code and their weight.
The rear sections are:
47462-52R short
47462-54R long
47462-60R long, light
Thanks for your interest