Hello from Augusta, GA

This is a long read and understand it comes from the perspective of someone who does not know you.
Wow, not sure what to say without it possibly being taken wrong. That's why I hate how the internet and text can easily be misunderstand when someone is trying to tell you something! Much rather communicate over a friendly beer in person! So please understand what I am about to say is meant as heartfelt advice and not in any way shape or form any kind of put down.
You need to take a good close look at yourself and your abilities as well as what you are about to undertake. I love KZ750's and have owned mine since it was brand new in 1980. I have owned 400's 650's and 250's as well. I have swapped the engines, re-ringed the originals and almost every other myriad of tasks that goes into keeping these things on the road. I have wrenched, lost blood and flesh, cried and cheered and gained a lot of satisfaction on a number of KZ's over the past 30 years, not bragging but letting you know I have some wisdom and insight about what I see in your pic's.
You have a lot of parts there and mistaking a timing cover off of an engine that has nothing to do with this bike does not bode well for your ability to handle this project going forward. You are going to have a lot of hours into this with an uncertain outcome. Also the prospect of more money going into this than it will ever be worth. Don't take me wrong there is a worth to building and riding something you have brought back from the dead that can mean more than money but dang dude this is a heck of a way to start. Just a quick search on Craigslist Augusta turns up a lot of KZ's, Some running and others projects. While up front purchase may be more than what you have here I think you are going to end up exceeding what a lot of them are selling for before you are done.
So all that being said, if you are going to take this on then you are in the right place, myself and many folks here will be more than willing to advise, supply parts (sometimes at no cost ) and just generally cheer you on because we all share a desire to see these bikes saved and on the road!
Take a hard look at yourself and whether you think you have the ability and drive to see this through. If so then go for it and I for one will be cheering you on and waiting for the finished result!

I get it man, Although the timing cover comment kinda struck a nerve...haha. No offense taken though.

So, my mechanical knowledge stops at dirtbikes. I've rebuilt my CR125, but that's a two stroke. I would LOVE to say i know stuff about car and truck engines...but i only understand the mechanical aspects. Haven't really turned any wrenches on em. All that is something i'm hoping to remedy through projects like this one and my diesel truck i just bought. Only way to learn is to get in there and try. So with that said, this thing is only $250. Worst case scenario i can part it out and AT LEAST break even.

I am more than aware of how much sweat, blood, money, and numerous cuss words this is gonna take outta me: WAY too much. You said it earlier, that there is a worth to building and riding something brought back from the dead. I agree, things are worth what time you put into them...so while it might not be the most financially responsible thing, and i may use up a lot of my time (i doubt netflix or hulu is gonna miss my company)...i think its something worth doing. I sure as hell have the drive, but the ability...that's something i know i don't have going into it, and something i hope to have by the end. I appreciate your insight on it all, everything you say is very realistic.

At this point I would start with a mock up of the engine in the frame and wheels. Put the cases together empty like you see on some of the mods here. Put the frame and all it's parts together, swing arm, steering head, forks etc. and see what you got. Then the side covers head light tail, sigs etc. Once you have a complete bike less the engine, install it and match up the mounts. Slide the barrels on and the head. Mock up the exhaust and carbs. If it all looks right, start on the engine. I say this so no money or very little is spent and you'll know you have a complete bike once you're done with the engine. Plus, when you're sitting there with a beer, admiring your handy work, you'll be more motivated to GET IT DONE BIKER. :woohoo:
Good luck.
Steve

Fixitmann is right but there is no reason why you can't be successful if you ask a lot of questions and are patient. It helps to have a ton of cash and and a lot of time too LOL
Remember at some point you are (hopefully) going to be barreling down the road at 70 MPH plus so this is no time for "good enough" or "I think this will work".
One last point... Knowing what I know now, I would not pay $250 for a disassembled MC. Too many better deals out there and that $250 pile of parts could end up costing you plenty. Maybe $100 if it includes a title.
Good luck,
Jim

I've bought, fixed and sold about 20 bikes in the past three years. That being said I have not bought bike in a box yet, and most are around $200. Many simply needing a carb cleaning and routine services

I did buy a 77 goldwing for $40 with a blown motor though. I'd maybe pay $100, but that's me

I know every nut and bolt in my bike. I've said before and I'll say it again, there's a certain satisfaction in knowing what's between you legs. :woohoo:
Steve
And you can fix it too.