That's not how you enter the giveaway. Click the link below and scroll to the bottom and post something to be entered.
https://www.cb750.com/threads/9087/
CB750 Supply has been a sponsor of this site for a very long time. They have a lot of carburetor parts: https://www.cb750supply.com/products/6/honda-fuel-system/37/ Maybe they'll have what you need.
The potential leak you're looking for would be between the engine and carbs. If you don't have a leak there, keep checking for other issues. I had a similar problem once with a Yamaha XS400 from the fuel mixture screws being turn in too much so it was running lean.
Good advice from @mrtwowheel
Many times the brake piston just won't retract and needs a little help. I'd bring a deadblow or rubber mallet and tap the calipers first. If that works, don't touch the brake levers or you'll have to tap them again. If they're more seized than that, remove the...