Finishing up the carbs for the Sandcast Project. It uses the very early 4-1 pull cables, so mechanical “bench syn’c” is a little different. First thing is to adjust all four cables equally slack so the slides all bottom out….. #4 carb refused to close up. Small gap under the slide, but definitely “hanging”. Crap. Did I put the slide in backwards?
Took #3 and #4 off the cables and pulled the slides to compare. Both cables had equal runout, so not that. Pulled the needles and both slides ran smoothly and sat down in the bores, no stickiness, no obstructions. Not backwards. Mmm.
Dropped the needles down into the carbs and #4 seemed to be stopping early and somewhat sticky. Pulled it out and it’s not bent, nice and clean. Get the micrometers out and carefully compare it to #3. Same dimensions, tapers appear identical. Pulled the emulsion tubes and they appear identical, both on OD an and ID. All the holes are clear and clean. Screwed #3 back in and smooth sailing. As I turn in #4 I can feel it dragging as I screw it in…. What the heck? Threads look perfect and then all the lights come on!! Check the second photo carefully the TOP of the tube is slightly tipped over (bent). The needle can’t drop down fully because the internal bore is NOT straight! How the hell did this happen?
I did get these carbs from someone else and I’m sure he didn’t know about this issue and honestly I can’t even imagine how it would happen? BUT IT DID. Fortunately I went through all my junk and found one in a set of carbs I haven’t used yet. Next time you think you have seen everything; think again. Put it all back together and called it a day.
