just saw this listing, at first look seems like a decent deal. https://atlanta.craigslist.org/atl/mpo/d/kennesaw-1973-yamaha-rd125-project/7492568518.html
It's a '75 not a '73. Missing the carbs. And it was pulled apart for some reason so it probably needs a lot more than first glance.
That said, they are really fun little bikes. In fact my RD125 is my favorite bike to take out for a putt, which I will be doing in a few hours.
Also those carb kits are wrong for this model. Those Keyster kits have #66 & #44 MJ & PJ. The US RD125B runs #94 & #44 and needs the KT-0160N kit.
And that intake manifold is for a different bike.