Panhead top tubes

[Lonnie]

I see on the Race Frame Engineering that there is a listing for the frame top tube (backbone so to speak) for panheads from 1952 on. I was curious, is there a difference between that tube and the one used on earlier 1948 - 1951 frames?

[Lonnie]

Anybody have any thoughts on this?

[Robert Luland]

I'd ask Steve Little him self at Race Frame Eng.

[Steve Little]

Hi. The wall thickness of the backbone for 1948-51 is 1/16" This backbone is fitted with a internal stiffener tube.
I,m not in the workshop so i cant check my information, but the wall thickness changed to 1/8" wall in (I think) late 1951. No internal stiffener for 1/8" wall backbone.
This also means that the seat post cluster has a smaller spigot for late 1951-1957.

[Lonnie]

Is the earlier tube being reproduced, Steve? Thanks...

[Steve Little]

Hi Lonnie
I will check if we have some in stock on Monday when we start back from our summer break.
Regards Steve

[Lonnie]

It just struck me that the later tube should be usable provided the inside portion at the seat post area was bored out so that the tube in just that portion was 1/16-inch. Does that sound feasible?
The reason I am asking all these questions is that I have a '50 that is supposed to have about 250,000 miles. The tube was cracked completely through. Also, the top motor mount had been welded, several times it looked like. I have jacked everything back in alignment, motor still in place, and it will be TIG-welded as far around as we can reach without damaging the rear pan cover or anything else. I want to see how it rides out before I have to break it down for the frame repair - a restoration is not planned. It would be crazy to send the frame off, wait forever, reassemble only to find the motor or transmission is weak.
However, knowing that at some point I'll need to have the frame professionally repaired, I should go ahead and line up the parts.
Thanks. Lonnie