I thin the newer CB400SF's run wider rims so as to maintain the shape of the tyre. Fitting to the older model would make the tyre higher in the center as the sidewalls would be squished together thus affecting handling. I was looking at doing this on my bike for new tyres but decided against it for that reason.

Hi

AVOID Avon Roadriders, in my humble opinion they're crap..

I've just changed my size to the later bikes sizes,
120/60 front and 150/60 rear, and with total success. Changing to this size has not affected the handling in any way.
I've bought Continental Sport Attack tyres, had the Road Attacks years ago and these are there stickier cousins.
So far they're brilliant and the bike handles like a dream, it's totally changed the bike.
The Roadriders felt twitchy and unstable in any weather, where as the sport attcks just grip and grip even in the wet.

Running Pirelli rosso's on bike at present, great for Australian conditions, good stickability...