Have a 76 CB550F that I did a mild cafe to.
Rotaryknight is on the right track. First make sure the bike is running well before modifying anything. It will be a lot harder to figure out any problems you might run into once you've started changing things around. Take a look at the wiring harness, make sure it's in good shape. If you're going to be doing the work, get a manual for the bike. But most of all, take your time and be patient. It will get frustrating.
If you're swapping out the exhaust, get a performance jet kit for your bike that has different size jets so you can fine tune your carbs with the new exhaust. Fine tuning may be harder if you decide to go with pod filters.
Other performance mods that I did but your bike is a lot newer and may not need it:
- Dyna coils
- Dyna ignition
- Progressive fork springs
- Braided brake lines
- Dual disk front brakes
- CB650 camshaft swap
Cosmetic mods:
- CNC'd top triple tree
- Finned covers and tappets
- Engine guards
- Tarozzi high rise clip-ons
- Chromed MC and lever
- Aluminum headlight ears
- Mini bikini fairing
- Mini speedo and micro tach
- Aluminum mirrors
- Oberon LED turn signals
- Oil filter adapter
- Integrated taillight
This off season I'm hoping to put in a box swing arm and a rear disk brake.
Good luck!