KZ250 D2 (81 DSR) project bike with no air box

I have just come into possession of a project bike, a KZ250 DSR (‘81 D2 I believe). I was told that it was seized, but it is not, so I’m trying to get it to a point where I feel comfortable attempting to start it. (Believe that it has not run in 15 or so years.)

In trying to just make sure everything is ‘there’, I’m realizing that I’m missing an air box, completely. The carb was just attached via the intake manifold. I’ve read a little on here about the mixed results with pod filters and the modified carb jets. I didn’t see that those were ‘for’ a 250 in the classified.

I’ve also noticed what I believe is the breather port (metal tube protruding upwards from the back of the engine, has a rubber boot that holds a 90-degree barbed fitting; bottom of this fitting looks like it has some sort of pressure release mechanism marked with an ‘F’. This has no hose attached but looks like it should. Did this originally connect to the air box? Is there an issue with just leaving it loose? It will spray oil vapor, correct? Any way to ‘deal’ with that?

So, I’m wondering: for the sake of testing, can I just run with an open carb safely, and if I go with a pod, are the performance issues impactful on a 250 for a first bike? Any other tips or suggestions in this area?

Other than that, I am slowly going through the engine and carb. I need to replace some gaskets, order a new petcock and fuel line, etc.. then hook up the new battery I suppose. Any other sage advice for someone trying to rehab an ‘81 KZ250 CSR?

A single cylinder will probably be okay with a pod filter or at least not as difficult to deal with as a multi-cylinder motorcycle. Try it but if there's any surging, then maybe install an extender or duct between the carburetor & air filter >> maybe use radiator hose or a rubber plumbing coupling.  The pod filter may lead to a lean condition, so you might need to get slightly larger jets. not sure, but keep an eye on the spark plug color.  If necessary, a simple shroud around the pod might help >> as a quick jobbie, maybe use a 1/2 gal milk jug or coke jug zip tied in place or something. 

note: the airbox provides a stable air intake environment plus it supports the carburetor. an unsupported pod filter can allow the carburetor to bounce & stress the carb holder there at the cylinder head causing an air leak &/or damage the carb holder.