Can I swap a fi motor into an early 80s honda cb750?

Looking to buy a 81 cb750 or around that time frame want to know if I could put a fuel injected motor in it without having to chop and weld alot of stuff, is it possible? Any idea what motors would work best?

No.

For a start you need to fit a fuel pump and filters to the tank.

If the replacement is liquid-cooled, and I think it probably will have to be, you will need to accommodate the radiator while avoiding the front wheel smacking it. Then the new engine is probably designed for a beam frame, so you need mounts. And finally, an ECU and all the sensors need to be mounted.

Why do you want fuel injection anyway? Carbs have been effective and efficient for decades.

CB750s were THE bike of their time, but if you swap the engine for a modern fuel-injected engine you will overwhelm the frame, suspension and the brakes, and once you have updated all that you could have bought a modern bike.

No.

There's no practical way to do it. Learning how to properly tune carbs, or even paying someone to properly tune carbs would be the only real practical choice. Sure, you will probably find someone who created an EFI cb750, but it wouldn't be cost effective or easy. It would be someone who had a passion for doing things the hard way and figuring them out.