Topic: Need help identifying some forks

[vorhese]

My buddy got these for his CB350 and they didn't fit (mismarked?). The O.D. of the tubes was way too big. He thought they might be for a CB750, and I needed new tubes.  The O.D. is 35MM but way different lower legs (lengthwise). Any ideas what these might be for?  Before I start tearing apart I wanted to see if anything is interchangeable.  Thanks.  My 76 CB750 fork tube and lower is in the center.

[ekpent]

If they look and measure the same use them

[Ricky_Racer]

I'd vote for a CB750A (automatic) since their fork lowers are slightly longer than from a "K".  RR

[vorhese]

You may be right, the rotor cover looks the same.

[754]

 I am thinking 77/78 750 K which may be the same as Auto..

 3 things they got going for them,
 Hardchromed tubes (better than aftermarket)

 Taller alowing use of fork brace..

 More stable due to deeper tube engament..

 .. run em..

[vorhese]

I finally got the tubes apart for a comparison.

The stock tubes/components are on the left side of the pictures.
Big differences are the tubes are same diameter, but ends have different sized holes. The unknowns have a different damper. The lowers and springs are longer on the unknown.


The steering dampers are different. The unknown does not have the rod across the diameter which allowed you to make a tool to hold it while tightening it. Which stinks if you don't have an impact gun / hex head attachment.


And they are shorter and slimmer.


So the ends of the tubes are different.


But luckily all the internals are a direct swap for the Cb750 lowers.  When assembled they sit the same height.


I'll be taking these tubes to get shortened by 2" at my machinist.

[Terry in Australia]

Frank's assumption is quite correct, the CB750F/F1, K7/K8 all had longer alloy sliders which is why they are highly sought after by Post Classic racers here, as they are able to be fitted with an aftermarket fork brace, and the longer tubes slightly reduce fork flex.

I've got a set off a K7 on my K1 with a Telefix forkbrace and 2 inch over CycleX fork tubes, and they work very well. Be aware though, that if you use them with OEM gaiters, the gaiters will be "scrunched up" due to their longer slider length.

Oh, and just a small correction, those damper tubes in your pic are fork dampers, not "steering dampers", that's a whole different kettle of fish......... Cheers, Terry.  

[vorhese]

Cool!

yeh, just a mental slip there with "steering dampers"