[Alex Zen]

I have had some CB350 fork tubes tapered to fit the top of my early 60's BSA top tree. The normal BSA fork tube bulges where they meet the bottom tree (the tubes I'm using are perfectly straight). Have any of you guys ever dealt with this before? I was thinking about shimming the bottom tree section and once the bottom tree is tightened down I should :fingers crossed: be ok. The other option would be to add material to the bottom tree and the cut to fit the cb350 trees. (The axle has already been machined to use the BSA front wheel)

The picture doesn't have the internal springs installed so the stance in no as low as it appears.

 

[Scavenger]

Yes they make bands to fit the spacing, most of the aftermarket tubes don't have the , taper to larger OD and came with shim bands

 

[Alex Zen]

Yes they make bands to fit the spacing, most of the aftermarket tubes don't have the , taper to larger OD and came with shim bands

from a place like Brit Cycle Supply Co or smaller type of shop?

 

[Scavenger]

Think just about anywhere really it's just an open band really , just like the clamps the go around the tubes that hold brake cables on bicycles ,,just flush..

You could maybe even get a band clamp,, trim it down to what you need and go

you need to measure your tubes then the ID and shim accordingly

In England in the '50's and '60's, things were still measured in inches. Stock BSA tubes are not a single diameter. The '66 tubes I measured taper out and get fatter (1 3/8") where they go through the lower tree. The rest is 1 1/4". Some aftermarket fork tube makers would give you a couple pieces if 1/16" shim stock to wrap around a single diameter tube. All the triumph tubes I measured (newest 1961) were 1 5/16" dia.

I supose it depends on your definition of "early" too. Many would say that early Triumphs and BSAs didn't have fork tubes but had girder forks.

 

[need louvers ?]

Get some long feeler guages of the right thickness (steel, please) and trim theem to length. Or even better, McMaster Carr sells trimable shim stock in sheets.

 

[Goldy]

You would be better off having proper spacers machined to fit...your life may depend on it.

 

[Scavenger]

Get some long feeler guages of the right thickness (steel, please) and trim theem to length. Or even better, McMaster Carr sells trimable shim stock in sheets.

Yes ,, the feeler gauge thingy works well too.

 

[need louvers ?]

You would be better off having proper spacers machined to fit...your life may depend on it.

I would have to very much agree with this, but I think the the gap he is trying to fill is a bit less than what can practically be machined. Edit: I just walked out to my shop (116 degrees!) and measured my '66 a65 and my '72 C.B. 350 and came up with a difference of about .055.

 

[Alex Zen]

the gap is very small. Two strips from a PBR can shimmed it. I would feel more comfortable w/ steel (maybe somehow cross hatched) so I think I will try the gauge idea. It would be awesome so have something made w/ a collar to hold it in place, but...?

 

[Alex Zen]

just testing. going to get extra feelers in a bit.

 

[55chevr]

Back in the day - Mid 70-s - everyone ran 6" over fork tubes. The BSA tubes used a steel band that was open. worked fine ... Ran and tracked fine. I had a 500cc twin and it ran out of steam at 100mph. But is had no handling issues.
Joe