You should never throw anything out. That's why my garage is such a mess, but occasionally, that can work for you. The front end on my CX500 sags terribly, the 32 year old fork springs are stuffed, but good new springs are around 100 bucks per pair, plus half of that again for shipping. I went for a dig around my garage though, and found a NOS of Progressive "Magnum" springs for something of the same era, Kawasaki KZ400, from memory. The side by side pic shows that the OEM Honda springs are 40mm shorter, but have a 94mm "Preload spring" added.
I machined up some hollow preload spacers from 20mm alloy bar. Anybody who's tried to stiffen their front forks with preload spacers will know what a PITA it is trying to balance a threaded cap on top of a spacer on top of a spring and then try to push the whole lot home while turning the spanner, trying the hell not to cross thread the fine thread on the top fork plug, which in my case, is alloy.
The top plug that I'm using is hollow, so I machined one end to fit snugly in the cap, and the other to fit snugly in the spring, and it worked great, nothing went flying, and I've still got both eyes and all my teeth. Also, because the new springs are 40mm longer much thicker than the OEM items, I reduced the length of the pre-load section to just 35mm, and when I screwed the new caps in, there was no sag in the forks at all. Bonus!
Now comes the fun part. When i was a wee lad back in the 1980's, air forks and air shocks were cool. Some manufacturers (Honda included) installed air forks and air shocks onto anything from cruisers, to tourers, to sportsbikes, and you could buy an aircap kit for your bike, if you were unfortunate enough not to have them already fitted from the factory.
The best kind were those that are linked, preferably with a goofy gauge to look at so you can check your air pressure (usually around 10 psi) and watch the needle go up and down as you brake and accellerate. Great stuff. Oh, and the reason for having them, was to take the sag outta ya forks too. In this case I didn't need them as my new "magnum" springs and preload spacers were more than adequate, but my old OEM fork caps were looking pretty crappy, so I was able to kill two stones with one bird, so to speak. With the kit installed, it's all fairly unobtrusive, but it does look "trick" in a 1980's kind of way.
Surprisingly, after I got back from a 4 hour ride, the gauge hadn't lost any air!
So now I've got a nice taught front end. Hmmnnn, I must install the new fender I bought, the original one is letting the side down somewhat!
Of course, when i took it for my ride it performed faultlessly, but as is always the case, I really notiiced the shortfalls of the rear shocks. The only ones I could find in my garage are the almost new ones I took off my Triumph Rocket III when I wasted 700 bucks on some progressive 440's, but they're just a tad too wide, so I'll have to keep looking.
Maybe a set of Golwing air shocks would be nice? Of course, if I could find some sweet Fournales air shocks of the era, I'd be in shock absorber heaven! Cheers, Terry.