Obstruction discovered in choke passageway in carb body. Pennies for your thoughts.

mrtask

mrtask

Well-Known Member
So some weeks ago I sent my HIF6s off to be refurbished. It has taken somewhat longer than I had hoped, due to circumstances beyond the control of the chap doing the work. He encountered a mysterious obstruction in a choke passageway in the body of one of the carbs. Repeated sessions in the ultrasound washer wouldn't shift it, and the bore was too small for him to be able to fit his endoscope down in there to take a look. He resorted to a mild acid solution, and that seems to have done the trick. Imagine my dismay when he told me it was "a bit of lead shoved down in there"!!! Gulp!
Anyway, I'm at a loss trying to figure out why somebody would do a bodge like that. Whilst I wait a little longer for the carbs to be reassembled and returned to me in tip top order, maybe somebody here has an inkling why that obstruction might have been inserted like that. I would welcome your insights.
 
could i have been a bit of lead solder from an attempted repair to the filter housing or similar perhaps, i once dropped some in a downdraught carb when soldering the choke cable to the grommet cos i couldnt find a small enough bolt. never did find it.
 
Interesting conjecture, Edmond. I don't run a filter housing anymore though, just K&N conical filters straight on the carbs, no elbows or can.
The refurb guy replied to my questioning what that was all about. He said;
"It had me puzzled. In the end the ultrasonic didn't get it. As a last resort I put a blow torch on it, and out it ran when body was hot. I have seen on other carbs like Webers etc. where people plug after the original plug has fallen out, but I've never seen that on SU carbs in 33 years of doing them. There is a first time for everything! I can only assume the theory behind it was to weaken the mixture on choke rather than fit new jets and set up correctly. Some of the things I have seen done by garages over the years were beyond belief."
 
yes, i can see that a worn or wrong size jet could be "repaired"by soldering the hole then drilling out to size , dont know how long this would last though . but sometimes needs must.
 
mrtask said:
Interesting conjecture, Edmond. I don't run a filter housing anymore though, just K&N conical filters straight on the carbs, no elbows or can.
The refurb guy replied to my questioning what that was all about. He said;
"It had me puzzled. In the end the ultrasonic didn't get it. As a last resort I put a blow torch on it, and out it ran when body was hot. I have seen on other carbs like Webers etc. where people plug after the original plug has fallen out, but I've never seen that on SU carbs in 33 years of doing them. There is a first time for everything! I can only assume the theory behind it was to weaken the mixture on choke rather than fit new jets and set up correctly. Some of the things I have seen done by garages over the years were beyond belief."
Click to expand...

Your intake set up sounds very interesting as I like to help an engine breathe better, so could I ask a couple of questions.
Is there much difference in intake noise?
What did you do about the flame traps, breathers etc.
Did you need to change the needles

Thanks in advance

Dochie
 
Dochie, induction noise is very much louder than with the standard elbows and air can. Flame traps are as normal, from the rocker covers to the carbs. Rear breather is not connected to anything. Needles are BAF.
 
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