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  1. #41
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    The biggest int jet I have on hand is a .032 so I will start there. Also going to bump the main to .070 because .068 is the smallest S&S recommends for big twins. I’ve been checking for intake leaks as I go, but of course one could have popped up so I will check before I try again. Motor is freshly rebuilt, less than 500 miles I would guess.

  2. #42
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    Very informative Thread on the Super-B's

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    Here's also a grand idea for a fuel atomizer ...



    Designed by Dan DaVinci ... Copied by Teddy ...
    Last edited by Dragstews; 06-08-2020 at 1:54 PM.

  3. #43
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    After doing a little more reading, I found a Super B thread on Jockey Journal where someone mentioned having almost the same issue and resolving it by fitting the carb with the stock S&S tear drop air cleaner. Today I upped the jets to .032 intermediate and .072 main and added the stock air cleaner setup, and the issue is completely gone.

    Looks like what I thought was a really bad overly rich flat spot in the mid range was actually the opposite this whole time. I was test riding the carb and trying to tune it with no air cleaner while I waited for some hardware to come in, along with a new filter element. I don't know if this just lets in too much air or it just doesn't meter it properly, but no matter what changes I made it still cut out/popped through the carb really badly because it was starving for gas/getting way too much air. It's not surprising that the carb likes the proper air cleaner, I guess I'm just shocked that it makes that big of a difference. I have seen other bikes with B's running no air cleaner at all.

    Anyways, it seems to be running well and pulling hard aside from a little off-idle hesitation which I should be able to tune out with some more work. I hope this helps someone else with a Super B. Thanks everyone for the help!

  4. #44
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    What do your spark plugs look like now that it's fixed?????

  5. #45
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    My super b is having the same mid range issues and I'm not going to put the factory air cleaner back on it so I'm into the lollipop idea
    Then after that maybe the air bleed trick if it's needed

  6. #46

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    Getting the mainjet to come in at the right time can be done pretty good with your air bleed. The tool that helps me the most is my air/fuel ratio gauge.



    I have an O2 sensor screwed into a bung welded into my front exhaust pipe, four inches down from the flange. It's helped me dial in my Weber triple really good.

    Wiseman

  7. #47
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    Have to pick up a few intermediate jets before I go to the air bleed the biggest I had was a .029 after that's then it's time to dial in the air bleed I don't have that space ship equipment so I'll just do it with lots of rest rides

  8. #48
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    Quote Originally Posted by Nobodyknowsimashithead View Post
    My super b is having the same mid range issues and I'm not going to put the factory air cleaner back on it so I'm into the lollipop idea
    Then after that maybe the air bleed trick if it's needed
    If it's cutting out/popping through the carb mid-throttle it's likely getting too much air or not enough fuel vs. an overly rich condition (this is what happened to me). If it's acting more flubby and sluggish mid-throttle it's probably too rich. I will say that for my bike (stock 74" shovel motor) I ended up with a .032 intermediate jet and .072 main using the stock air cleaner and I may even bump it up one more.

    I also just got a Yost Power Tube per Dragstews rec and plan on trying that soon to see if it makes a difference.

  9. #49
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    What do your plugs look like????????

  10. #50
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    BTW if you want to more positively retain a Super B (doesn't work with Es whose backing plate isn't flat nor thin enough for spot facing) air cleaner cover you can do what I do and drill the three mount towers straight through then use long stainless screws or bolts with locking nuts behind the backing plate.

  11. #51
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    I've got a 74 main and a 29 in it now and am gonna basically just have a bird deflector over it ( I got a plan to make one out an old hd belt buckle) but it's just open for now when I open it up the 74 seems ok but 32 or 33 range was where I planned on starting I did also put in a yost power tube after reading about it here carb tuning is fun to me so this is cool I did also pick up a couple lectrons at a swap a few months ago to try out after this

  12. #52
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    Quote Originally Posted by Tattooo View Post
    What do your plugs look like????????
    This is after coming back from a 20 minute ride, the plugs weren't brand new prior so the reading might be thrown off. They were previously pretty black from a Super E that was running rich but have leaned out since then with the B. I have no way of shutting off the bike under load and pulling in the clutch like people say to do to see the mid range reading so this is after idling.

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  13. #53
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    Quote Originally Posted by Nobodyknowsimashithead View Post
    I've got a 74 main and a 29 in it now and am gonna basically just have a bird deflector over it ( I got a plan to make one out an old hd belt buckle) but it's just open for now when I open it up the 74 seems ok but 32 or 33 range was where I planned on starting I did also put in a yost power tube after reading about it here carb tuning is fun to me so this is cool I did also pick up a couple lectrons at a swap a few months ago to try out after this
    Did you notice a difference with the power tube? I haven't installed mine yet

  14. #54
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    Hard to say since the jetting wasn't correct when I installed it

  15. #55
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    If anyone is interested it seems that the jet combo for me on a probably stock 74" motor with no air cleaner drag pipes and a yost power tube is a 36 and a 74 leaving things a little on the fat side and that's at 600ft above sea level here in the midwest

  16. #56
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    Bringing this back from the dead for some more fun. I've been running the B on my shovel with drag pipes and angled lollipops, stock air cleaner setup, .036 intermediate and .074 main jet, air bleed drilled to .062 and Yost Power Tube installed for about 2 months now. For what it's worth, I don't recall really feeling any difference adding the power tube, so I'm not sure it was worth the $39. I'm still feeling a bit of a flat spot in the mid range, plugs are sooty black after a ride but the pipes near the motor are blueing which would make me think it's running lean/hot (or the chrome just isn't that great). Other than that it runs mostly smooth, idles nice and starts up fairly easily most of the time.

    I recently picked up another used B with Thunderjet installed and I'm cleaning it now. Reading the Zippers instructions on thunderjet tuning, they also mention tuning the air bleed but this one looks like it's still stock size. Wondering if it's worth messing with this carb to try and escape the mid range richness by sizing down on the main jet because the thunderjet kicks in shortly after (from what I am reading). Or should I drill out my air bleed more on the carb I'm currently running? Thoughts?

  17. #57
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    Quote Originally Posted by HogsRear View Post
    Bringing this back from the dead for some more fun. I've been running the B on my shovel with drag pipes and angled lollipops, stock air cleaner setup, .036 intermediate and .074 main jet, air bleed drilled to .062 and Yost Power Tube installed for about 2 months now. For what it's worth, I don't recall really feeling any difference adding the power tube, so I'm not sure it was worth the $39. I'm still feeling a bit of a flat spot in the mid range, plugs are sooty black after a ride but the pipes near the motor are blueing which would make me think it's running lean/hot (or the chrome just isn't that great). Other than that it runs mostly smooth, idles nice and starts up fairly easily most of the time.

    I recently picked up another used B with Thunderjet installed and I'm cleaning it now. Reading the Zippers instructions on thunderjet tuning, they also mention tuning the air bleed but this one looks like it's still stock size. Wondering if it's worth messing with this carb to try and escape the mid range richness by sizing down on the main jet because the thunderjet kicks in shortly after (from what I am reading). Or should I drill out my air bleed more on the carb I'm currently running? Thoughts?
    The Tjet probably won't help you on a stockish motor, but the instructions can be applied to your carb without the Tjet. Lots of good information there.

    For both you guys on this thread running .036 intermediate jets, that is a mighty big jet for a Super B on a relatively small motor. But I always say, give the motor what it wants.

    As far as running no air cleaner box goes, here's the thing with the Super B, and E for that matter. The bowl vent is on the face of the carb where the backing plate is mounted. Without the backing plate, air passing by the bowl vent can create a vacuum in the bowl and cause the carb to lean out. On the Super E, there is another vent passage with a plug that can be removed and/ or installed in the bowl vent on the carb face. With the Super B, I think you have to drill a new hole into the vent passage to accomplish the same thing. ANY of these carbs running no air cleaner, a velocity stack, or really any non-S&S air cleaner, will usually benefit from this modification. I think the B vent mod is covered in the Tjet instructions.

    Jim

  18. #58
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    The T-Jet instructions says to drill a 11/32" hole and then theard with a 1/8 NPT Tap ...
    That's a huge hole for venting the float chamber...

    Here's how I went about that mod ....



    Used a fitting from the Shovel Aluminum Primary era, pressed it into a drilled hole, ran a hose back to a weedeater fuel filter for filtered air to inter the bowl ....

    Birthday Boy ...
    (Tomorrow I'll be somebody else)
    Last edited by Dragstews; 08-09-2020 at 10:35 AM.

  19. #59
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    Quote Originally Posted by JBinNC View Post
    The Tjet probably won't help you on a stockish motor, but the instructions can be applied to your carb without the Tjet. Lots of good information there.

    For both you guys on this thread running .036 intermediate jets, that is a mighty big jet for a Super B on a relatively small motor. But I always say, give the motor what it wants.

    As far as running no air cleaner box goes, here's the thing with the Super B, and E for that matter. The bowl vent is on the face of the carb where the backing plate is mounted. Without the backing plate, air passing by the bowl vent can create a vacuum in the bowl and cause the carb to lean out. On the Super E, there is another vent passage with a plug that can be removed and/ or installed in the bowl vent on the carb face. With the Super B, I think you have to drill a new hole into the vent passage to accomplish the same thing. ANY of these carbs running no air cleaner, a velocity stack, or really any non-S&S air cleaner, will usually benefit from this modification. I think the B vent mod is covered in the Tjet instructions.

    Jim
    I came to the 36 intermediate by just test runs it seemed large to me too but it ran like shit with a 33 in there
    now I will say this my front plug is always considerably more rich than my rear Ive been through all the o rings and replaced them and rechecked for leaks and double and triple checked pushrod adjustment idle mix is set rich to just before an rpm drop and I'm at a loss for why the front plug is borderline too rich and the rear is borderline too lean I have noticed what looks like fuel residue coming out from the vent and the air bleed holes so I'll dig up some thunderjet instructions and drill the vent hole you mentioned

  20. #60
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    Quote Originally Posted by Nobodyknowsimashithead View Post
    I came to the 36 intermediate by just test runs it seemed large to me too but it ran like shit with a 33 in there
    now I will say this my front plug is always considerably more rich than my rear Ive been through all the o rings and replaced them and rechecked for leaks and double and triple checked pushrod adjustment idle mix is set rich to just before an rpm drop and I'm at a loss for why the front plug is borderline too rich and the rear is borderline too lean I have noticed what looks like fuel residue coming out from the vent and the air bleed holes so I'll dig up some thunderjet instructions and drill the vent hole you mentioned
    A normal H-D with a single carb on the usual shared intake, and a cam with the same timing front and rear, will show slightly lean on the front cylinder and/or slightly rich on the rear cylinder. You have the opposite condition, which would indicate to me that you have some kind of mechanical motor problem. Could be nothing more than a little vacuum leak, or even an ignition timing problem.

    Jim

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