Topic: 75 500T forks on a 76 550F

[rlarkin70]

So when I took apart the front end on my 76 CB550F I noticed the right front fork is bent. it's probably off by about 1/4" at the end.  The stamp says "341" on it, and it is a mirror image of the left fork.

I found a set of forks from a 75 CB500T and I am wondering if they would fit.

My main concerns are:

Will my brake caliper fit the left 500T fork?
Will the fender fit properly and bolt onto the 500T fork?
Could I use the same (progressive) springs that are in my 550F shocks?
Down the road, could I mount a second brake caliper to the right 500T fork?
Is the length the same?
Can I can use the existing triple-tree pieces from my bike, or if I would have to use those from the 500T?

Thanks for any input. I have searched a lot of threads...will this fork work on this bike, what fork can I use, etc... but I couldn't seem to find anything definitive about 500/550 compatibility, and also if a 500T is the same as a 500F when it comes to the forks.

-Ron

[bryanj]

in order
Yes
Yes
Not sure check their site
Yes
Again not 100% sure you need to measure the steel tubes
Top tree is different I think, with different clock/bar mountings

[rlarkin70]

hi Bryan- Thanks for your input. That's good news, it sounds like I can make them work. Which is nice, since I already bought them! For $20 they seemed to be in good shape, they had the same lower shock bodies, and same tube diameter. The only difference is they don't use the rubber boots (which is fine with me, I like the look without them). I think I can just use my existing triple trees and slide them in. I will confirm this as soon as I install them, in case anyone wants to do the same thing down the road.

[paulages]

hi Bryan- Thanks for your input. That's good news, it sounds like I can make them work. Which is nice, since I already bought them! For $20 they seemed to be in good shape, they had the same lower shock bodies, and same tube diameter. The only difference is they don't use the rubber boots (which is fine with me, I like the look without them). I think I can just use my existing triple trees and slide them in. I will confirm this as soon as I install them, in case anyone wants to do the same thing down the road.

i think you'll want to use the stock trees. i'm told that 400/4 folks use 450T and 500T trees with 550 forks to achieve the original trail, but with 35mm forks. i would assume then that the 500T has a comparable trail to the 400 but would change your 550 for the worse.

[Jerry Rxman Griffin aka MuthaF'er]

HAVE YOU CROSS REFERENCED THE PART NUMBERS?? If not please do so. If they are the same they are the same! If they are different part numbers then I don't have an answer. I'll be glad to put you on the road to where to find this info and show you how to do it.

My headlight bucket and other pieces for my 75 750F are the same part numbers as the 550F and the CB500T!!

Jerry

[bwaller]

You can straighten the fork tube, especially if it's only bent slightly. Paulages is correct the 500T steering stem offset isn't the same as your 550, but the forks are both 35mm.

[rlarkin70]

no, I honestly didn't think to check the part numbers!  good idea.      I have the parts list for the 550 on my computer, and I can download the one for the 500T.  I would imagine the complete units would be different part numbers though, since the 550 fork has a boot, and the 500T fork has a dust seal. maybe I will check the tube part #s.  In any case, like I said, for $20 plus shipping, I went ahead and got them.

As for bending the forks back, I did consider it...but decided against it for a couple reasons. One is that I don't have the equipment to do it. Also, the same fork would also require the removal of two sheared bolts (that mounted the fender). The cost of getting those bolts drilled out and inserts put in was more than I paid for the new 500T forks. Plus the idea of heating up the tubes and beding them back scares me. I've read that this can introduce stresses and points of failure, and for the cost of new forks I figured that was the best route to go.

My plan is to use the stock 550 triples and the 500T forks. The tubes are 35mm on each, and based on the numbers and measurements on the bottom part, they are identical to the ones that came off the bike. So I think it should work.

I will let you know how it goes! Thanks for all the advice.

-Ron

[paulages]

I would imagine the complete units would be different part numbers though, since the 550 fork has a boot, and the 500T fork has a dust seal.

this is only true for the '77-'78 cb550. the earlier K's and the F's have the same gaitors you speak of. the fork lowers are different for the late model 550's as well, standing about an inch taller. this shouldn't matter at all though.

[bryanj]

Boots and dustseals are a direct swap as long as you use the appropriate headlamp ears

[paulages]

Boots and dustseals are a direct swap as long as you use the appropriate headlamp ears

not true-- the late model lowers are taller than the early models intended for the boots. i know--i tried using the boots on my '77 forks, and they bunch up too much.

[rlarkin70]

well, looks like the 500T forks will work just great. the lowers are IDENTICAL, and everything will mount up just fine. The only difference is the tubes and springs. The 500T tubes are 3/8" shorter than the stock 550F tubes, and the springs are also shorter. This will in fact work out for the better, since I wanted to lower the front and rear end of the bike slightly from stock. I am using some aftermarket headlight brackets, and no boots.

-Ron