Nessism wrote: Carb kits should be avoided since the brass parts are typically of inferior quality to that of the original Japanese Mikuni parts. Sometimes they are unavoidable though.
This is what he means , the brass is softer the taper is different and the groove for the O-ring is way too shallow
the thirty seven year old one is on the top.
Installed 4 years ago
Every O-ring looked like that.
The O-rings on the original screws were intact so I cleaned up the old screws, threw fresh rings on and they went in like butter
I cleaned out the Pilot circuit as per "chconger's" recomendation, thanks for that.
I thought that I read somewhere that on a 78 26mm carb the pilot screw is backed out 1 -3/4 turns