Modernisation? But the back brake is very good on the CB-1 if in good state of maintenance, it's a caliper that's still used on various new bikes.
She's looking good, very good In the same way as mine - like she came from the factory that way.
Thought about using 92-99 CBR900RR rear footrests to give more space to have the exhaust higher? The sidestand is also a bolt-on fix for your higher ride height - I see the wood you need to keep it at a good level
Is your chain worn out? Or too long? Either way, it's loose, and you are out of adjustment possibility. Best sort that quickly!