Hey Flatlander,
I just followed your CB550 link... I know what I'll be reading tonight. Looks like I'm heading down a path not too different from yours, 23 pages of project.
Is a "fork brace" a part or is it a project? If a project, can you point me to a picture of a well executed one?
if you did read my complete thread then you must have come across the part about the fork brace
my path is a slipper one that leads to lots of time and money spend on something that doesn't even look like that much was put in it so probably a complete waste, ha ha!
a fork brace itself is a part. it creates an additional bridge between the legs to stiffen the construction. the early 550 legs are shorter than later ones, you and i both have those. there is no commercially available brace for them, that fits over the tyre. i had mine made by t-kat, a guy who custom made it. he's got the measurements now and his cnc programmed so could turn out one for you. many don't like it's chunky look but it certainly adds a lot of stability.
a more subtle look is the tarozzi that only fits the later, longer for legs and is available off-the-shelf if you want that you'd have to get a hold of a pair of the longer ones from a later 550 and change them, i think the k3 or f2 models had them.
but if you put your front fender back on and do the things that stev-o and scott suggest, your frontend will already feel much better and the overall ride will be more stable. a brace can be an addition that, if you like to push the envelope and especially if you add more power to the engine, improves the handling a lot. generally speaking, for a bike that's actually being ridden i'd always use a fender unless you love getting spray and grit all over the bike and yourself.
if this bike is a keeper for you, work out your suspension, brakes and general chassis first before doing anything else, it will really make it feel a lot more confident.