Went to replace the old jet on the rear carb which seemed too long with a new one, and was somehow not surprised to find the new jet had too small a diameter opening for the ZH needle to seat like the old one. This is new from IPD; I'm guessing it's for some B20 needle.

The old (original) jet, which held my ZH fine but could not be adjusted correctly measures 70mm in total length, the brass sleeve accounting for 39 of those mm's. The Diameter of the opening is about 3mm. This jet's sleeve is 3mm longer than the forward jet, which works splendidly.

The new jet is the corresponding 67mm, but the aperture is just shy of 2mm.

I know better than to drill it out, but I don't know how to specify the correct dimensions when re-ordering one. Both have black plastic bases.

And a brief rant: why did I find too long a jet in the carb in the first place? Why is the new jet not the right size for ZH needles is they're so prolific?

And so, my problems I heap in front of your collective experience to sort out. Have mercy.
-Sean
--
1966 122s; 1970 142s