Ebay: 330272274639 Unfortunately at that price I'll be tempted....
I have a pair of originals, unfortunately even with a re-chrome they'll never be perfect, but I think I'll have to be happy with that. You can buy aftermarket ones from the States for around $200 a pair, but poor quality according to reports. http://www.apexcycle.com/cb77.htm As an aside, I sorn'd the CB today, last taxed 01-07-82. No wonder it was a bit dusty.
Rough rule of thumb is everything fits both CB72/77, I think the only differences are engine top end (larger bore and head to fit), carbs and sprockets. It's a real challenge getting non-rip off parts for this project, bloody Thailand sellers got loads of NOS but at outrageous prices - $100 for a rear brake cable, plus postage of course.