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Discussion Starter · #1 · (Edited)
Hey guys, just a quick question on this S&S Super B Carb Ive got on this 71 Iron Head Sportster. It only really seems to want to run decently with the Accelerator Pump ON...Ive tried adjusting the low idle screw with it cold and hot but doesnt seem to make a difference. Quick Background...the bike sat for about 15 years untouched...I went through and did a basic tune up on it INCLUDING a new Carb kit...but then it sat for another 5 years :eek:( ...However the bike is now in MY garage where I can work/ride it much more often :eek:). Ive been told i should change out the Carb completely but dont really wanna do that. Just wondering if im missing something maybe timing or clutch that may relate or should i just order another carb kit and tear it down?
 

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Retired citizen
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I've got a Super B sitting on my shelf right now ... no accelerator pump ! The "E" has an accelerator pump !
I'm thinking you might be referring to the enrichener knob.
 

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Red and White
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So with a "B" carb you have no accelerator pump... meaning: You can't rap the throttle and get a nice response. You have to roll into it slowly. I have a "B" on my Shovelhead. It's just something you have to get used to if you are going to keep that carb. Otherwise you need an "E" like Schmidty said. I have an "E" on my Ironhead and my Road King both. They are great carbs. Or you can go the Mikuni route. It's another good carb.

If you keep running it with the enricher knob out then you are going to foul your plugs in no time. I only use that when it's really cold out and then I only use it to get the bike started before setting the idle with the throttle / throttle screw.


-Rohan
 

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I like both the Mikuni's and the Super E's (especially the newer ones with adjustable air bleeds).
 

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Discussion Starter · #5 ·
Apologies, I must be referring to the "Enricher valve/knob"....looks like i might have to do another rebuild on it. Like I said it doesnt really wanna run with the knob down/closed. Whats the deal with a super B that has a Thunderjet? I see one for sale not to far from me but am unfamiliar with it....would that perhaps supply the more fuel at lower RPMs or does it serve a different purpose?
 

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Adds more fuel at WOT high RPM.

If you are going to buy a different carb, get one with an accel pump.
 

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Retired citizen
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If the slow screw isn't making a difference then that could be that the slow jet is plugged. Drop the bowl and remove the slow jet for inspection.
 

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Wayward Son
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Whats the deal with a super B that has a Thunderjet?
Adds more fuel at WOT high RPM.
:nod
Was always told it was sort of a band-aid to cure the S&S`s short comings.
Until later versions built one in so to speak.

If you do decide to go with another carb. Do not rule out a properly done CV.
Some companies offer already modified ones too.
Only my opinion, but. An S&S is a lot of carb for a stock(?) Sportster.
 

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Apologies, I must be referring to the "Enricher valve/knob"....looks like i might have to do another rebuild on it. Like I said it doesnt really wanna run with the knob down/closed. Whats the deal with a super B that has a Thunderjet? I see one for sale not to far from me but am unfamiliar with it....would that perhaps supply the more fuel at lower RPMs or does it serve a different purpose?
The Thunderjet covers the flat mid range spot that most S&S carbs suffer from.
 
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