Auxiliary vent screw ?

mml03102

Active Member
I have trying to use the ss carb tuning guide you people suggested and I did the adjustments and its seems okay at slower speeds but on the highway I cant keep a steady speed it starts to stumble and loses power until I give it more throttle, I put a Big Dog spiked air cleaner I bough on it and in the ss guide it says when you change the intake you should always remove the Auxiliary vent screw , where the hell is it , do I have to remove the carb and if so should I re jet it while its off? :flag:
 

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mml03102

Active Member
I see that but I didn't see that on the carb I understand the other 2 pictures -top and bottom but Im guessing you have to remove the lower half of the carb to see that picture with numbers 10 through 14, is that so? and should I also replace the main jet while Im there and if so any idea what Harley jet size and part number would be the right one for a replacement
 
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JimNubs

Member
Easy fix

I removed my aux. vent screw a couple of years ago. I did not have to disassemble the card in any way.
 

mml03102

Active Member
Ill have to get a better light and stronger glasses and take another look, did removing the screw make a difference for you?
 

BWG56

Guru
here's an idea, use a mirror and hold it under the carb, the screw is to the rear, under the enricher, you don't have to remove the bowl
 

RRRUFF

Well-Known Member
Don't have to drop the bowl to remove the Auxiliary vent screw but you may have to up the Main Jet air bleed #13 also. I had to when I went to the S&S Dual Runner intake. Don't remember the jet sizes but I can look if it will help you at least find a starting point.
 

francoblay1

The Spaniard
Check this thread out, or do a search and you will find plenty info about this subject: http://www.bigdogbiker.com/forums/fuel-air/14439-what-jets-do-you-run.html

About the Air Bleed Jet... older Carbs have a fixed one... if that's the case you can drill it or replace it with a normal main jet. somewhere here you will find which Carbs do have the interchangeable and which don't... it all about the letter their serial # starts with.

:cheers:
 
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francoblay1

The Spaniard
I assume this stumble started with the spike correct?
This was my case, as soon as I got rid of the Vent Plug Screw all problems stopped. Also most people, including myself, finds it does make a huge difference if you run the spike vertical, good improvement.

:2thumbs:
 

mml03102

Active Member
I tried the mirror and still cant see it or even a whole where it might have been , it might have been removed before because it had a forcefinder on it when I bought it and I replaced it with the spiked air cleaner but because of the weather here I was unable to take it out before changing to the spike but Franco if you say it cleared your problem up when you removed your I will def find that lil fucker,lol and maybe try the vertical.
 

francoblay1

The Spaniard
I tried the mirror and still cant see it or even a whole where it might have been , it might have been removed before because it had a forcefinder on it when I bought it and I replaced it with the spiked air cleaner but because of the weather here I was unable to take it out before changing to the spike but Franco if you say it cleared your problem up when you removed your I will def find that lil fucker,lol and maybe try the vertical.
It has to be there!!! :lol: It does not protrude... it has to be taken out with an Allen key.
 

mml03102

Active Member
I guess Im a dumb ass ,lol. I miss read the ss diagram I didn't realize the picture was flipped and I was looking to the right in the rear under the carb but I did find it and it has already been removed so I will have to figure out what jet to replace it could be the intermediate according to ss. I adjusted the carb to there instructions but riding down the road it was backfiring while decal so I would slowly turn the idle mixture screw to the left until it stopped and it ran fine until I get on the highway cant hold a steady speed because it starts losing power until you give it more throttle , I will have to read up some more but it sounds like the intermediate jet?
 

BroadBand

Since late 60's
k I need all the help I can get,lol
As a suggestion, try searching youtube videos.
Sometimes, seeing it done is helpful if the instruction sheets get confusing.
You could start HERE, but a search on S&S jetting & tuning on the youtube.com page just might get you going...
 

BWG56

Guru
I tried the mirror and still cant see it or even a whole where it might have been , it might have been removed before because it had a forcefinder on it when I bought it and I replaced it with the spiked air cleaner but because of the weather here I was unable to take it out before changing to the spike but Franco if you say it cleared your problem up when you removed your I will def find that lil fucker,lol and maybe try the vertical.
Take a pic of the bottom of the carb and post it, maybe we can point it or the area out for you.
 

HMAN

I just like my Freedom
Supporting Member
You'll have to drop the bowl to check, but you may not be able to replace your airbleed jet. I have an older super G and it has the drilled. 040 airbleed. I need to send it to S&S to have a changeable one installed. Keep us up on your findings....
 

john sachs

Well-Known Member
You'll have to drop the bowl to check, but you may not be able to replace your airbleed jet. I have an older super G and it has the drilled. 040 airbleed. I need to send it to S&S to have a changeable one installed. Keep us up on your findings....
Block off the non-adjustable air jet hole in the carb, and install an air jet externally.
John
 
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