fork swap

If you can use a lathe, mill, welder, you should be able to adapt almost any set of forks using aluminum upper and lower triple clamps. But it won't be easy, it might not be inexpensive and you might end up making changes to your frame (headstock) that are irreversible.

To begin with, the SR headstock (part of the frame the steering stem fits into) is quite short compared to most modern sportbikes and it has a relatively small diameter. Then, the bearing receivers are designed for ball bearings and are very shallow compared to modern tapered roller bearing receivers. It's doubtful that you will find a set of modern upsidedown forks suited to a direct swap since modern frames are designed for cornering forces undreamt of in the 1970's and use larger components to handle those forces.

To deal with these issues, you might have to fabricate a new steering stem and/or bearing receivers to adapt the replacement forks to the SR frame. If you make new bearing receivers, I expect you would have to weld them to the headstock, which will introduce a number of other complexities into the process (alignment, warping, non-originality).

That said, you can buy tapered roller bearings that fit the receivers in the SR headstock and are suitable for stock forks and early (88-96) GSX600/750 and maybe GSX-R model forks, which might be as good as the SR frame is up to managing. The Suzuki forks are conventional telescopic style but are larger diameter (41mm) and a pound or so lighter than stock according to Solo2Racer (who has posted extensively on how to do that conversion). They also permit use of light weight modern wheels, which may be the biggest advantage.

Of course any non-original parts swap can set off a cascade of other mods required to put the bike on the road again. In the case of a fork swap, you get into headlights, turn signals, electrical controls, brakes, fenders, wheels, and tires. Making it look easy is the trick.

Bill

Following your lead and instructions Solo2Racer (Ken), I mounted a set of GSX600 forks in a SR500 frame (which is why I appeared so well informed on the subject ). You must use tapered bearings for the SR frame, the ID of which fit the Suzuki stem.

As for the 3/16" spacer, I placed mine on the lower part of the steering stem (above the lower triple clamp) which worked well since the Katana bearing surface is almost an inch high and the SR bearings are under a half inch high. Maybe that obviated the need for a longer bolt to hold the upper clamp. I haven't worked out a "stop" for the forks yet, it will probably involve welding tabs to the headstock.

One thing I like about the Katana forks is that the steering crown (or upper triple) seems to have enough material surrounding the clipon retaining bolt that I should be able to thread modified SR500 handlebar clamps into the crown and use standard "sit up and beg" style handlebars. I am way to old and creaky to ride a bike with clipons.