68' CB350 slipping in 3rd gear

Hello all, new to the Honda twins but not new to bikes. About 2 hours ago I purchased a relatively clean 68' CB350 that runs and rides but needs some work. Here are the issues I am having. 1. it slips in third gear so bad you have to shift to 4th or the bike wont move. all other gears grab. 2. it wont get past 60mph and it wont do wide open throttle at all. If I do WOT it acts funny and doesn't really accelerate. 3. I don't know exactly what its supposed to sound like, but to me it seems a bit clicky, as if it needs a valve adjustment. I am running stock everything with the exception of some clubman handlebars. Any advice is greatly appreciated.

Start from the beginning. Clean the carbs. Adjust valves and timing to stock settings. Adjust clutch properly. Until you set everything to factory specs you'll just be chasing problems in circles.