Topic: 78 Cb550 .. Stiffer Fork spring recommendations. ??

[evopgt]

On my bike,  78 cb550. Are there any Fork springs available out there that you guys recommend that will stiffen the forks and to minimize the travel?? I put new seals in and 15wt fork oil.  Still seems a little soft and slow to return to height after braking. Thanks guys.. I've also read of spacers between the cap and spring?? But this seems rigged to me?  Thoughts? I see some different brands of progressive springs available, are these stiffer than stock??

[calj737]

Those spacers are "pre load" spacers which basically reduce the compression travel. Progressive rate springs are popular, as are Single rate springs if they are ordered based upon YOUR RIDER WEIGHT. If you're above average height and weight, Single Rate springs with some preload spacers can make a huge difference. If you're close to average, Progressive springs tend to be an easier value.

If you are okay with a non-stock modification, cartridge emulators with single rate springs are a very nice upgrade. It allows "tuning" of the damping and compression beyond the preload and spring rates.

[evopgt]

Can you buy the spacers anywhere?? Or is this something  I should fabricate myself? I'm about 5 11. 225lbs.  I raised the forks through the triple about 1 1/2" and want to make sure travel is limited a little more to prevent bottoming out. I'm assuming stock springs are single rate?

[przjohn]

You can just use small pieces of PVC pipe for preload spacers. Get a small length at the hardware store and start out with like a 1" long piece and see how it feels.

[evopgt]

Thanks.. I'll try it out.    Maybe metal would be better?

[Scott S]

 The PVC is fine. Add a washer between the spring and spacer if you want.
 I've always found Progressive springs (and shocks) to be very stiff, even when I've called them and supplied them with rider weight, bike weight, intended use, etc. That's just my personal opinion.

[calj737]

Be aware, sliding the forks up thru the triples reduces the clearance of the lower stem to the tire. If the travel is exceeded, tire conflict ensues.

Verify that you filled the fork with the correct amount of fluid too? Should be right about 6.5oz. The stock springs were mildly progressive, but they may we'll be worn. At your size, I'm not surprised they feel mushy after 40 years either. New springs for you!

[evopgt]

Yes CalJ. That's what I'm concerned about mostly. I want the look of the lower front , but want to be safe also. I'm also going to add a front fender to keep any death wobbles from occurring. The fender should also provide a barrier between the triple and the tire should I hit a speed bump at 50. I'm gonna try a 1" spacer on each fork. , if I don't like it I'll buy new springs.   Thanks guys. Always helpful.

[scottly]

Stock 550 springs are progressively wound. 750 springs are straight-rate springs, and vary in length depending on the year; early have a shorter spring with a steel preload spacer, and late have a longer spring with no spacer.

[flatlander]

chances are that the 40 year old original springs are tired and mushy. replacing them is a good starting point.
progressive seems to be a favourite brand in the US. over here in europe, and maybe also available there, wilbers makes springs that are progressively wound and a bit stiffer for more sporty ridinig, and wurth are generally a bit softer for comfort.
if you buy new springs they usually come with a recommendation for oil weight and amount. amount can be measured from the top, i.e. hight of oil level in fork. make sure it's fully extended when you measure, i.e. front wheel off the ground.

you say you want to minimise travel. why? you expect lower bumps than honda anticipated? if you use spacers to fine-tune spring preload you will of course affect travel but i don't see the point of minimising travel for its own sake, unless you ride under very controlled conditions?

when buying fork oil, be aware that the weight indication on the bottle often has nothing to do with the "real" weight and varies between manufacturers. here's a good reference: http://www.peterverdone.com/wiki/images/a/a7/PVD-ISO-Viscosity-Data.gif

[Deltarider]

What about your rear shocks? Are they functioning OK? Are they still the original 'bicycle pumps' or have they been replaced. 

[evopgt]

Rears are replaced

[evopgt]

Can I buy shorter Fork tubes?? Where?

[evopgt]

Never mind.. just read the hazards associated with that.  Sheesh