Making the plastic joints is easy......but costs a fortune if you want to go the plastic injection route.

Other thoughts would be casting PVC, alloy or brass parts. I've been machining some alloy molds recently for various carbon projects and I don't think it's too tricky to make a simple mold for these joints....Hmmmm.

Anyhow, I've just come up with a potentially cheaper solution, but I'll have to speak to my mate first.

Needles are a big problem. I had another mate carefully measure all the needles I have for various NSR's (stock and HRC) from the year dot, but trying to come up with a match is very difficult. At least I have the dimensions now and know somewhere that will make them, but not exactly cost effective for a small batch.

Other jets such as mains, pilots, pwrjets etc are easy to get.