CB550 1978 F2 Front Fork Springs

[Neilw]

I've been working on my 1978 CB550 F2 front springs today, changing seals and the oil.

I checked the length of both springs, one is 465mm and the other 473mm. I also found a rather large nut being used as a spacer / packer at the top of each spring - see photo.

The bike was a non runner, so i have no idea how it handled, but i'm wondering if i should just remove the erroneous nuts and go with the springs i have?

What do you think of this setup as is. is it ok? or should i find replacement springs.

[taysidedragon]

I'm not claiming to be a suspension expert but having springs different lengths can't be good. Random nut spacers could be there for all sorts of reasons, previous owner may have had strange ideas of 'improving' suspension.  They could be an attempt to make up for sagging tired springs .
Check the correct length of spring specification and, if necessary buy new springs. 👍

[Neilw]

I'm not claiming to be a suspension expert but having springs different lengths can't be good. Random nut spacers could be there for all sorts of reasons, previous owner may have had strange ideas of 'improving' suspension.  They could be an attempt to make up for sagging tired springs .
Check the correct length of spring specification and, if necessary buy new springs. 👍

They are outside of specfication, in so much as they exceed the original length, but that seems common with after market springs i've found. They are well within spec for wear.

All i can think of is perhaps whoever did it wanted a stiffer front end! The rear shocks are Koni, so also an upgrade.

I'm going to reassemble and try them as is, with no additional spacer nut and see how i get on. Changing the springs is a simple process, so always an option if things don't work out.

[Oddjob]

The nuts were fitted to add some preloaded to the springs. You can buy some top fork nuts that will do the same thing these days.

[Neilw]

The nuts were fitted to add some preloaded to the springs. You can buy some top fork nuts that will do the same thing these days.

Ok, Great, had to ask Chatgbt what that was, got a clear explanation - thanks.

[Oddjob]

No problem mate. You’ve learned something new so not a wasted day.

Btw, if your fork top nuts are very rusty, and most are, you can buy some polished stainless steel ones these days for probably less than genuine Honda ones. Just for info.

[K2-K6]

Its now fairly routine in bigger MTB forks to do tbe same in packing the preload to get ride height correct.

They're called "tokens" in there, and proprietary hard plastic that can be clicked together in addition for gaining more distance.  There's general use of fork stanchion @ 40mm diameter too for racing purposes. 
Some also use internal spacer that screws inside the spring coil to change the rate of spring by making section of coil incompressible, gives effectively a shorter wire length,  which lifts the spring poundage without changing the spring.

Looks here that maybe previous owner was in need of jacking the front generally with the longer spring + spacers fitted.

[Orcade-Ian]

Neil,
I have a pair of springs from my 550F1 - they both measure 476mm - I bought brand new ones as the front end seemed a bit firm and I was not sure if these were original or aftermarket.  The new ones made no noticeable difference and were exactly the same length as the ones I removed.  You can have them for a small donation to the Forum - I'll pay the postage if you PM me with the details,

Ian

[McCabe-Thiele (Ted)]

It must have been a craze, my 500 had a similar arrangement of preload spacers fitted, not a nut but a section of steel walled  tubing
I ditched the spacers, my springs were both the same length and within the length range when not compressed as per the manual.

[taysidedragon]

It must have been a craze, my 500 had a similar arrangement of preload spacers fitted, not a nut but a section of steel walled  tubing
I ditched the spacers, my springs were both the same length and within the length range when not compressed as per the manual.

Some bikes have tube type spacers fitted as standard. My old Trident 900 had them.

Homemade experimentation usually consists of a stack of washers but some nuts fit nuts, or whatever they have available of the right size!