Progressive Type Fork Springs

[hc243102]

It all started with ordering some new fork seals, and then I ran across some Progressive Type Fork Springs  http://www.vintagecb750.com/products/82/monthly-sales  that were pretty cheap so I said "what the hey".  With this being the first time I've ever worked on the forks of my bike (750K8) I have a few questions. 1. Is there any special tools that I may need, outside of the normal set one would have (ie, low pressure air pump, etc.) and 2. Will I now have to upgrade my rear suspension to progressive to match the front? I plan on doing this someday anyway, just not now (unless of course I have to).

[sgtslag]

I installed the Progressive brand Fork Springs, along with their airless shocks, at the same time.  The handling was transformed, turning my 1979 K model into a machine that handled every bit as good as my son's 1993 Yamaha FZR600 sport bike.  I like it so much, I did the same thing on my 1993 Kawasaki Voyager (heavy) touring bike.  I will do the same on my next bike, as well.  The quality of the handling, as well as the safety improvement (wheels tracking the ground, instead of flying over it), is incredible.

It's been posted, on other forums, that if you do not upgrade both at the same time, the upgraded end will make the deficiencies of the OEM suspension glaringly obvious (it will handle/ride poorly until you upgrade the other end).  This makes perfect sense, as the two ends work in conjunction with each other, so if one is failing, you will feel/experience it.

Generally, once the Progressive Fork Springs are installed, you will no longer need, or want, air pressure added to the forks -- this will make it too harsh, and stiff.  My Voyager had air-assisted forks, and rear, OEM shocks.  I don't use air in the front anymore, and the new rear shocks have no air input -- simpler, easier to maintain/use, and even more comfortable/better handling than the OEM ever was.

Just my experience, and what I've read.  YMMV, but I sort of doubt it.  Cheers!

[sgtslag]

Front Fork Springs:
Regarding 'special tools needed,' no, you won't need anything unusual.  The old springs come out, the new ones go in, with/without spacers added; new fluid is added, as per the instructions for your bike, from Progressive (the amount used with the progressively wound springs is different as the springs displace a different amount of fluid).

The direction of the springs does not matter, except that they both go in, the same way.  Other than that, it won't matter which end is up/down, as long as they are the same.

Rear Shocks:
For the rear shocks, I took one off at a time, replacing it with the new one.  On the Honda, it was easy:  the springs were pre-installed on the shocks, so I just replaced the rear shocks, one at a time.

Depending upon who is selling you the rear Shocks, they may, or may not, come with the springs installed on the Shocks.  If they are installed for you, just swap out the old for the new, one at a time.  If the springs are not pre-installed for you, then you will need to either rent/borrow/purchase a spring compressor tool, or make one from clamps you have.

Making your own spring clamp is dangerous!  If it should slip off, that spring will have incredibly dangerous force when it erupts from the clamp!...  Be careful!

I took mine into my mechanic to have him mount the springs, and the shocks, on my Voyager -- it was easier, and safer.  Labor costs were minimal, and it was done without injury, or property damage.  Cheers!

[TOOLS1]

You will find a tutorial on replacing fork seals in this thread. http://honda-cb750-s.456789.n3.nabble.com/My-Buddie-s-POW-MIA-K-3-and-How-to-do-fork-seals-duel-disc-breaks-and-engine-rebuild-td3283036.html#a3306102
TOOLS

[hc243102]

So I changed the seals, wasn't too bad, thanks for the tutorial by the way. While it was apart I swapped the stock fork springs with the new PROGRESSIVE TYPE ones. The new ones were a little shorter and came with spacers. Got it all back together and now it just don't feel right. I put exactly 5 ounces of ATF as per the K8 workshop manual. I know that the new springs should have a stiffer feel, but now whenever the forks compress it feels like a cheap pogo stick (like a dry spring sound). Does this seem right?

[TOOLS1]

No that does not seem right. Before getting too worried, try adding 1.5 oz of ATF. Also the progressive springs should start soft, and get progressively stiffer.
TOOLS

[hc243102]

Took it for a short ride today and it felt alright on the road. However I'll try adding some more to it and see how it does.