Super B Carb Questions
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Road Captain
Joined: Feb 2006
Posts: 507
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From: Cleveland, OH - Longing for Savannah, GA
Super B Carb Questions
Hello,
I have a 1983 Shovel 5 speed FLT. The motor is stock with a fresh top end and a mild street cam. I am running fishtail mufflers that are baffled. I have a super B carb and upon reassembling the bike after painting it idles fine and under load/throttle runs like crazy, however at a constant cruising speeds it spits, sputters and coughs. I have done nothing to the engine or fuel system any different than before I took it apart for paint other than changing the faulty petcock out with a brass on/off type.
My fuel/air mixture screw was adjusted the same as before tear-down but was running so rich i was fowling plugs and blowing black smoke out the tailpipes along with fire......I turned the fuel input down and the needle is basically out only a half to 3/4 turn only...... it idles and picks up on the road okay but at a constant cruising speed or getting going from a dead stop it sputters, etc. I spent an hour trying to adjust and ride the bike to overcome the issue, but became exhausted and disgusted.
Is there anyone that may have some pertinent info that may help me with this problem?
Any advice would be greatly appreciated. Thanks in advance.
I have a 1983 Shovel 5 speed FLT. The motor is stock with a fresh top end and a mild street cam. I am running fishtail mufflers that are baffled. I have a super B carb and upon reassembling the bike after painting it idles fine and under load/throttle runs like crazy, however at a constant cruising speeds it spits, sputters and coughs. I have done nothing to the engine or fuel system any different than before I took it apart for paint other than changing the faulty petcock out with a brass on/off type.
My fuel/air mixture screw was adjusted the same as before tear-down but was running so rich i was fowling plugs and blowing black smoke out the tailpipes along with fire......I turned the fuel input down and the needle is basically out only a half to 3/4 turn only...... it idles and picks up on the road okay but at a constant cruising speed or getting going from a dead stop it sputters, etc. I spent an hour trying to adjust and ride the bike to overcome the issue, but became exhausted and disgusted.
Is there anyone that may have some pertinent info that may help me with this problem?
Any advice would be greatly appreciated. Thanks in advance.
Seasoned HDF Member
Joined: Nov 2006
Posts: 12,878
Likes: 5,449
From: la la land jerzey
Hello,
I have a 1983 Shovel 5 speed FLT. The motor is stock with a fresh top end and a mild street cam. I am running fishtail mufflers that are baffled. I have a super B carb and upon reassembling the bike after painting it idles fine and under load/throttle runs like crazy, however at a constant cruising speeds it spits, sputters and coughs. I have done nothing to the engine or fuel system any different than before I took it apart for paint other than changing the faulty petcock out with a brass on/off type.
My fuel/air mixture screw was adjusted the same as before tear-down but was running so rich i was fowling plugs and blowing black smoke out the tailpipes along with fire......I turned the fuel input down and the needle is basically out only a half to 3/4 turn only...... it idles and picks up on the road okay but at a constant cruising speed or getting going from a dead stop it sputters, etc. I spent an hour trying to adjust and ride the bike to overcome the issue, but became exhausted and disgusted.
Is there anyone that may have some pertinent info that may help me with this problem?
Any advice would be greatly appreciated. Thanks in advance.
I have a 1983 Shovel 5 speed FLT. The motor is stock with a fresh top end and a mild street cam. I am running fishtail mufflers that are baffled. I have a super B carb and upon reassembling the bike after painting it idles fine and under load/throttle runs like crazy, however at a constant cruising speeds it spits, sputters and coughs. I have done nothing to the engine or fuel system any different than before I took it apart for paint other than changing the faulty petcock out with a brass on/off type.
My fuel/air mixture screw was adjusted the same as before tear-down but was running so rich i was fowling plugs and blowing black smoke out the tailpipes along with fire......I turned the fuel input down and the needle is basically out only a half to 3/4 turn only...... it idles and picks up on the road okay but at a constant cruising speed or getting going from a dead stop it sputters, etc. I spent an hour trying to adjust and ride the bike to overcome the issue, but became exhausted and disgusted.
Is there anyone that may have some pertinent info that may help me with this problem?
Any advice would be greatly appreciated. Thanks in advance.
The only thing that can cause a steady throttle spiting back like you have is the low speed jet might be clogged, dirty -- from the carb not being held in an upright location when it was off for the top end work soooo remove it and clean it - if you need an explain what one it is and or the location just ask - jz
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Road Captain
Joined: Feb 2006
Posts: 507
Likes: 0
From: Cleveland, OH - Longing for Savannah, GA
jz,
Thanks for the reply. I did have the carb off and cleaned the carb as well......I removed and blew out the jets, too. They seemed really clean. I will remove the secondary again and soak it and blow it out with compressed air again.
If this is not the issue, could it be possibe my secondary is too small?......but how could that be if it picks up under load?
confusing stuff
Thanks for the reply. I did have the carb off and cleaned the carb as well......I removed and blew out the jets, too. They seemed really clean. I will remove the secondary again and soak it and blow it out with compressed air again.
If this is not the issue, could it be possibe my secondary is too small?......but how could that be if it picks up under load?
confusing stuff
Seasoned HDF Member
Joined: Nov 2006
Posts: 12,878
Likes: 5,449
From: la la land jerzey
jz,
Thanks for the reply. I did have the carb off and cleaned the carb as well......I removed and blew out the jets, too. They seemed really clean. I will remove the secondary again and soak it and blow it out with compressed air again.
If this is not the issue, could it be possibe my secondary is too small?......but how could that be if it picks up under load?
confusing stuff
Thanks for the reply. I did have the carb off and cleaned the carb as well......I removed and blew out the jets, too. They seemed really clean. I will remove the secondary again and soak it and blow it out with compressed air again.
If this is not the issue, could it be possibe my secondary is too small?......but how could that be if it picks up under load?
confusing stuff
sometimes you cant clean a jet like some think we just replace it than we know for sure whats up with what is going on -- jz
Club Member
Joined: Mar 2009
Posts: 66,128
Likes: 51,461
From: Niles Canyon Ca.
How long are the fishtails ? The Super B does not get along well with long pipes . Here's a few of the common problems , there's a small vent port on the side of the carb that tends to plug when it does they start sucking more gas hence the false rich characteristics at speed . Second is the throttle shaft that holds the butterfly tends to wear and they suck air , B's are very prone to this one . At an idle while warm take a can of brake cleaner and give a small shot or two around the shafts and at the intake clamp's she drops off you've got leaks .
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Seasoned HDF Member
Joined: Jul 2012
Posts: 9,511
Likes: 13,828
From: Pa.
Is everything set up the same now, except for the new cam, as before the top end? I would bet that tweaking your secondary jet will help. Sounds like it needs to be just a little fatter.
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