Hi, I am also the owner of CBX400F.
I bought it in 1983 as new moto and I keep running still now. In these years, I have less chance to run enough then total milage is arround 90000 km. Before I saw this motorcycle and CB750F which had been released just before the CBX 400F, I was interesting in only bicycle. Even 2 wheels cycle, motorcycle was not. Actually, the design of the before CBX was very old. At least it had not a feel of the new technology. (It is the feeling of mine but 20 years ago, now I have a different viewpoint for old motorcycles.)
But after CBX was running in town, I found it and I decided to ride on. I did not touch the engine to make more power because I bought it for the design and the feature. I had less interest for running fast, sometimes I went to a long touring all arround Japan.
Also in 20 years, I modified a little. Initialy, I wont a model F2 which has a big fairing but I could not do for less budget. 2 years over, I found an accesory kit at Honda SF shop then I putted a fairing and more on my moto.
It is different color of the fuel tank and tail fin. Yes, I replaced them 10 or more years ago because it damaged by rust. Actually, I have to say thank you to my moto for long an stable running. I also want to ride on it from now too.
I think it is important to keep condition while a long stop that you
place the machine in the house or somewhere it is isolated from the open air.
I am living in Ishikawa prefecture and it is near by Japanese sea.
Every year I have to stop to run and place it into my garage because
it is always a lot of snow arround here.
Even winter, so much frost will cover the body for high hummidity.
And more, it is rusty condition too because it is seaside.....
It is better you spray CRC or some plastic protection liquid before you
store the moto.
And use motorcycle cover with old blanket.
Whmmm. There is no special technique....
Please check your moto freaquently. That is all.
Sorry for long message, see you!
keigo kitanisi (yesugei@po.incl.ne.jp)