Anyone know if this is possible? Not having the sf here in the states I'm left looking at photos. Eyeballing that sweet cyclone system yoshi makes. At the very least I assume modifications may have to be made to move mounting brackets and mid pipe changes. If the headers clear think I could manage.

As far as I know it is exactly the same engine. Which means the headers will bolt onto the engine. As for the rest of the system it would be more of a try it and see thing as mounting brackets will more then likely be different.

I don't think they are the same engine- the CB-1 uses gear driven cams while the CB400 SF uses a chain. That, combined with the difference in the suspension setups leads me to believe it won't be quite so easy to mount the exhaust from one onto the other. HTH.