KR/XLR frames

Racing K Models

KR/XLR frames

Postby hugoct » Fri May 24, 2019 5:32 pm

Has anyone done an analysis regarding date changes on the KR frames? The 47006-52R frame has 21 revisions with the neck angle change of 2 degrees as the seventh change on October 15th of 1953. The last change was April 16, of 1970. 7/16/52 holes added for mounting the small gas tank, 11/19/52 52 steering head replaced with 53R steering head. 10/15/53 steering head pulled in 2 degrees. 12/11/56 steering head replaced with 53RA steering head. (my guess is this would be the 57R casting). The 57006-58R frame gets 9 revisions with a change to the steering head angle in February 4th of 1966.
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Re: KR/XLR frames

Postby MSJC » Sat May 25, 2019 12:56 pm

Great info! I have a few frames with the 57R neck. if you have anything you wanted me to inspect on them let me know and can report back with pictures. most have good legible date codes some do not. Also a question for you, I have a few early frames that are void of mounts on the rear downtubes. they have the earlier neck casting but the tomahawks don't have the obvious machining for the bolt on KR section that my later frames do. Does any info you have access to shed any light on this? If the mounts on the rear down tubes have been removed it was by someone with a very steady hand as the tubes look and feel untouched. Also I have heard tell of a light KR frame. is there any way of identifying these and would they be correct for an XLR/KRTT or only the KR?

thanks for posting and let me know if I can help in any way.
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Joined: Thu Jan 24, 2019 7:00 pm

Re: KR/XLR frames

Postby 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
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