I have an extra fuel rail from a later model 240 that is sitting in my office as "art work". I was going to use it to make a tool for cleaning injectors...used an uglier one for the tool, since I had to braze the intake end shut so that the cleaner could be injected via the shrader valve. Worked like a charm and I can clean 4 injectors at once. If you make one, a Noid tester can be used one at a time or 4 Noids at once will do all of them quickly.
Good luck,
el raidman