Looking for help with Fork Tube Identification

[WannaBeFabrication]

I picked up a whole bunch of extended fork tubes with a hodge podge of different models. Some of them are labeled "Yamaha 650" but no year. I'm pretty positive that these are all NOS from 1976 (that's the year on all the newspapers used to pack the boxes) and the guy I bought them from said he thinks they might be from Forks by Frank.

 

[arcticXS]

34 mm is 76 or older, 35 mm is 77 or newer. That's the basic stuff.
However, there may be some differences at the bottom end of the 34 mm tubes. I once bought some extended XS650 34 mm tubes for my RD350. I just cut them at the top, and re-threaded them in the lathe. The RD350 damper rod arrangement fit into those tubes without any issue. More recently, I purchased another 34 mm set from MikesXS, and IIRC, those were different at the bottom end. Maybe someone can shed some light on this issue, 72-76 forks?

 

[DogBunny]

The tubes in the pic that you labeled "34mm" appear to be 1972-1973 XS2/TX650 aftermarket fork tubes.
The tubes in the pic that you labeled "34.5mm" appear to be 1970-1971 XS1/XS1B aftermarket fork tubes.

 

[gggGary]

Franks is very likely, they are located in Evanston Illinois.

 

[Beags64]

Any of 'em going up for sale? Would be interested in a pair for XS1B

 

[arcticXS]

The tubes in the pic that you labeled "34mm" appear to be 1972-1973 XS2/TX650 aftermarket fork tubes.
The tubes in the pic that you labeled "34.5mm" appear to be 1970-1971 XS1/XS1B aftermarket fork tubes.

Any difference between 72-73 vs 74-76?

 

[DogBunny]

Any difference between 72-73 vs 74-76?

I don't know. Most of the individual part numbers are different, but I don't know if there are any significant differences.
I looked into it a little further, and I'm no longer even sure about what I wrote in post #3. I think what I said is true, but I'm not 100% sure.

 

[WannaBeFabrication]

Any of 'em going up for sale? Would be interested in a pair for XS1B

All of them are up for sale. I believe the 34.5mm are all 10” over tubes

 

[WannaBeFabrication]

The tubes in the pic that you labeled "34mm" appear to be 1972-1973 XS2/TX650 aftermarket fork tubes.
The tubes in the pic that you labeled "34.5mm" appear to be 1970-1971 XS1/XS1B aftermarket fork tubes.

Thanks for that info. The only thing I have is that the 34mm tubes all have the label “yam 650 up to 71” on them and the 34.5mm tubes just say “yam 650” so I’m still just a little confused.

 

[DogBunny]

Thanks for that info. The only thing I have is that the 34mm tubes all have the label “yam 650 up to 71” on them and the 34.5mm tubes just say “yam 650” so I’m still just a little confused.

Yeah, I wrote a mea culpa in post #7 saying that I'm not so sure on my I.D.s. Sorry about that.
It might help me and others a lot if you could provide pics of what the bottoms of the tubes look like.

 

[WannaBeFabrication]

Yeah, I wrote a mea culpa in post #7 saying that I'm not so sure on my I.D.s. Sorry about that.
It might help me and others a lot if you could provide pics of what the bottoms of the tubes like.

The pictures I provided are of the bottoms of the tubes.

 

[DogBunny]

The pictures I provided are of the bottoms of the tubes.

Your pics show the sides of the bottoms. I meant the bottoms of the bottoms.
I can now confirm that the tubes in the pic that you labeled "34.5mm" ARE DEFINITELY 1970-1971 XS1/XS1B aftermarket fork tubes.
I'm still not sure about the other pic. A pic of the bottoms of those tubes might help.

 

[WannaBeFabrication]

Sorry about that little misunderstanding. Here you go
Top picture is the 34mm
Bottom is the 34.5mm

 

[gggGary]

Any info on where the newspaper is from?

 

[DogBunny]

A few months ago I talked to someone who had Frank make a set of tubes for him. Not NOS, but new made-to-order. I talked to this person long enough ago that I don't remember who he was or the details of the conversation, but the upshot was that there was a certain amount of fitting and machining that had to be done to the new tubes. This was by design, it's how Frank makes them.
As I've said, your 34.5mm tubes are for 70-71, and appear to be ready to be used as is.
Your 34mm tubes will probably work for all of 1972-1976, but need to be modified. I think the intention is that you remove the parts inside the bottom of your old tubes and put them in the new ones. I believe that on 1972-1975 the internals inside the bottom of the tube are held in with a circlip. I think you would have to cut a groove into the new tube to accept the circlip. I'm not sure about any of this, and more work may be required.