I'd like to replace plumbing on my '92 CX such as fuel lines from fuel tank to filter to fuel rail, etc. with some Aeroquip ones.

How do I find the correct size so I can buy the right size Aerquip adopters and fuel hose?

 

Why don't you cut a small section off of the pieces that you need and either measure them or take them to your local tuner shop and tell them what you need. Or you could do it the easy way and look up the size of them in the Honda manual

 

Finding the hose size is easy. But how do you know what size fittting to use? Like what size thread is it?
For one, I know that the Banjo bolt that goes into the fuel filter for the Civics are 12x1.25.

Helms manual covers the torque specs but doesn't cover a lot of the bolt sizes.

 

If you have a stock gas tank, you can't change that out to the fuel filter. It is all hardline anyway, so going to braided hose ins't going to help you there anyway..

The only place you can use AN fittings and hose is between the top of the fuel filter and the fuel rail. Which is pretty useless under 300 HP or so.

And if you are using a stock fuel rail, you can't get away from using a banjo fitting there.