Topic: F-model fork tubes OK in K-model lowers?

[the architect]

I need to replace the badly damaged (rusted, corroded, pitted) fork tubes on my CB750K.  I may have found some ~77 tubes from a CB750F.  Can I use them in my stock lowers?  

I found a reference table indicating that they are both 35mm diameter.  The parts sheets looks like the inner parts may be slightly different.  The '77 F-model tube doesn't seem to include the plunger (item #9) that is found of the K-model.

1975 CB750K



1977 CB750F


If this is not a good cross, what would be a suitable range of donors to look for?  I understand that later models went to hard-chroming, thus increasing their durability.

HELP!  I want to get on the road.

[the architect]

Anyone, anyone?

 

I found some I'd like to snag if they'll fit.

[crazypj]

You may need to get part number 7 in lower picture although I would just try and fit hydrualic lock into tube first (if it goes in there with a close fit, don't worry about it.)

PJ

[Toxic]

I have done it with no problems.

[kos]

Works great. Used it on a Daytona winning bike at AHRMA races, no problem.


KOS

[lordmoonpie]

+lots - works fine.....as long as you don't have early K0 fork leg lowers which are wider to allow for the fork piston. I tried this out - ended up with very wobbly bendy fork legs until I realised...DOH! 

....did I just admit that out loud? 

[the architect]

Thanks guys!!  You're the best!

So, is this a straight swap, or do I need to buy extra parts to make to two work together?

My other question is length.  Are these notably longer or shorter than those on my '75 K-model?