CHOP CULT HOME
Email Password
Search
Page 2 of 5 First 1234 ... Last
  1. #21
    Senior Member

    Content on this page requires a newer version of Adobe Flash Player.

    Get Adobe Flash player


    Join Date
    Sep 2010
    Posts
    12,789

    Default

    A S&S Cycle "GBL"
    Carburetor would be better suited to your model ...

    Last edited by Dragstews; 05-25-2020 at 7:56 PM.

  2. #22
    Member

    Content on this page requires a newer version of Adobe Flash Player.

    Get Adobe Flash player


    Join Date
    Sep 2015
    Posts
    91

    Default

    Potentially dumb question. I picked up another B for cheap so I figured I would clean it out and see if it was any different. Are these two holes in the bowl supposed to connect? The other side of the bowl has a matching pair of holes with a slightly larger opening clearly connects but this seems blocked. Click image for larger version. 

Name:	865A5F27-0F37-45FD-B029-6CE31B8872A7.jpg 
Views:	0 
Size:	92.7 KB 
ID:	103881

  3. #23
    Senior Member

    Content on this page requires a newer version of Adobe Flash Player.

    Get Adobe Flash player


    Join Date
    Dec 2018
    Posts
    2,107

    Default

    Yes, those two holes connect, same on both sides of the bowl. One is the intermediate jet well, and the other is the enrichener tube well. The hole at the bottom of the enrichener tube well is small, and acts as a jet to meter fuel to the enrichener. The intermediate jet well has a larger hole serving it, with the jet serving as the jet.

    Jim

  4. #24
    Member

    Content on this page requires a newer version of Adobe Flash Player.

    Get Adobe Flash player


    Join Date
    Sep 2015
    Posts
    91

    Default

    Quote Originally Posted by JBinNC View Post
    Yes, those two holes connect, same on both sides of the bowl. One is the intermediate jet well, and the other is the enrichener tube well. The hole at the bottom of the enrichener tube well is small, and acts as a jet to meter fuel to the enrichener. The intermediate jet well has a larger hole serving it, with the jet serving as the jet.

    Jim
    Thank you Jim! I figured it's there for a reason, but right now it's definitely blocked. I believe this is the enricher side. I blew it out with compressed air and have been poking at it with a pick but doesn't seem to be connecting. It almost seems like the small hole on the inside of the bowl just isn't deep enough, but I'm going to keep at it.

  5. #25
    Senior Member

    Content on this page requires a newer version of Adobe Flash Player.

    Get Adobe Flash player


    Join Date
    Dec 2018
    Posts
    2,107

    Default

    It's small. I use one strand from stranded electrical wire to probe those holes, and small holes like intermediate jets. Solvent and air pressure will get it eventually.

    Jim

  6. #26
    Member

    Content on this page requires a newer version of Adobe Flash Player.

    Get Adobe Flash player


    Join Date
    Sep 2015
    Posts
    91

    Default

    Got that passage cleared and tried it on the bike the other day. Similar to the other B, no surprise, but less severe flat spot/cutting out in the mid range. I drilled the air bleed tonight to 1.4mm (.055"). I plan to try it again in the next day or so and will report back. It currently has a .031 intermediate and .070 main.

  7. #27
    Senior Member

    Content on this page requires a newer version of Adobe Flash Player.

    Get Adobe Flash player


    Join Date
    Dec 2018
    Posts
    2,107

    Default

    Quote Originally Posted by HogsRear View Post
    Got that passage cleared and tried it on the bike the other day. Similar to the other B, no surprise, but less severe flat spot/cutting out in the mid range. I drilled the air bleed tonight to 1.4mm (.055"). I plan to try it again in the next day or so and will report back. It currently has a .031 intermediate and .070 main.
    Your main jet is fat. The intermediate may be OK, usually .0295 or .031 work well.

    Jim

  8. #28
    Member

    Content on this page requires a newer version of Adobe Flash Player.

    Get Adobe Flash player


    Join Date
    Sep 2015
    Posts
    91

    Default

    Quote Originally Posted by JBinNC View Post
    Your main jet is fat. The intermediate may be OK, usually .0295 or .031 work well.
    What’s a good starting point for the main? 66 or 68? It’s a stock shovel motor.

  9. #29
    Senior Member

    Content on this page requires a newer version of Adobe Flash Player.

    Get Adobe Flash player


    Join Date
    Dec 2018
    Posts
    2,107

    Default

    Quote Originally Posted by HogsRear View Post
    What’s a good starting point for the main? 66 or 68? It’s a stock shovel motor.
    One or the other will probably be the one. You will have to tune a little. You really need to get the main right before you start changing the air bleed, provided that you can run past the midrange blubber and get a clean wide open pass or two. At higher speeds and with the throttle wide open, if you roll off the throttle a little and the motor picks up, it's too lean. A good long hill, half mile or more, is a good place to really load the motor when tuning.

    Jim

  10. #30
    Member

    Content on this page requires a newer version of Adobe Flash Player.

    Get Adobe Flash player


    Join Date
    Sep 2015
    Posts
    91

    Default

    I did one quick pull the other day when I was running the bike, slight uphill in third gear to see if it would smooth out past mid range and it was still breaking up but I only tried it once. It had a .066 main at that time so maybe I’ll try a .068
    Last edited by HogsRear; 06-03-2020 at 6:14 AM.

  11. #31
    Member

    Content on this page requires a newer version of Adobe Flash Player.

    Get Adobe Flash player


    Join Date
    Sep 2015
    Posts
    91

    Default

    Ok so just tried it again with the current setup – .031 intermediate, .068 main, air bleed drilled to .055. Still getting a noticeable flat spot and some popping through carb in mid range but I think this is the smoothest it’s been yet. Past the mid range it smooths out and pulls strong, so I think the main is pretty close. For the record, I’m doing these test runs with no air filter on but I plan on installing the stock s&s tear drop. Just waiting on the backing plate to come in.

    Now before I make any other changes to the air bleed, should I try dropping the intermediate to a .0295 to lean it out in the lower range? Wouldn’t that also lean out the mixture as it changes from low to high as well, which in theory would help smooth out this flat spot more? Just want to make sure I understand as best I can what these changes are doing.
    Last edited by HogsRear; 06-03-2020 at 2:36 PM.

  12. #32
    Senior Member

    Content on this page requires a newer version of Adobe Flash Player.

    Get Adobe Flash player


    Join Date
    Dec 2018
    Posts
    2,107

    Default

    Yes, leaning the intermediate should help the fat transition. That will help your fuel mileage. But, a rather lean intermediate on a carb with no accelerator pump may give you an off-idle flat spot which can be helped by making the idle mix a little on the rich side. But overall low speed acceleration may suffer, especially on a shovel if you are not kinda rich on the intermediate.

    Round and round it goes, you determine when it's good enough to stop messing with it. (But when it's good, it's a pleasure to ride!)

    Jim

  13. #33
    Member

    Content on this page requires a newer version of Adobe Flash Player.

    Get Adobe Flash player


    Join Date
    Sep 2015
    Posts
    91

    Default

    Appreciate all the insight Jim, thanks. I think I’ll try the smaller intermediate jet now and work on the mixture like you said. If there’s still an issue I can open up the air bleed to .060 and see how that does.

    I’ve read too many threads on here that leave no solution to problems after pages of reading so I’m trying to keep this updated as well. Will report back!

  14. #34
    Senior Member

    Content on this page requires a newer version of Adobe Flash Player.

    Get Adobe Flash player


    Join Date
    Aug 2009
    Posts
    2,927

    Default

    As JB stated, the B has no accelerator pump.
    It's a "roll on" only carb.
    But that can be changed...
    I'm a fan of the "super bowl" but not a fan of the Bendix style plunger it uses.

    Tune the bike for good response with a smooth twist of the wrist.
    If you want to be able to flick it.
    Swap carbs or add the pump.

  15. #35
    Member

    Content on this page requires a newer version of Adobe Flash Player.

    Get Adobe Flash player


    Join Date
    Sep 2015
    Posts
    91

    Default

    Quote Originally Posted by Sky View Post
    Tune the bike for good response with a smooth twist of the wrist.
    If you want to be able to flick it.
    Swap carbs or add the pump.
    Yep, I understand but this is not the issue. I had a Super E on before, it worked well enough and I might end up going back to it eventually. But I'm trying now to figure out how to make a B (without a super bowl) work well on my bike because I know it's possible.

  16. #36
    Member

    Content on this page requires a newer version of Adobe Flash Player.

    Get Adobe Flash player


    Join Date
    Sep 2015
    Posts
    91

    Default

    Tried the .0295 int but had the mixture screw more than 3 full turns out so switched back to the .031. Drilled air bleed to .062 and hardly noticed any change from .055. Still cutting out/popping through the mid range when I roll on the throttle. This was surprising and now I’m scratching my head again because I was expecting for that jump to make a difference.

  17. #37
    Member

    Content on this page requires a newer version of Adobe Flash Player.

    Get Adobe Flash player


    Join Date
    Sep 2015
    Posts
    91

    Default

    I referenced the S&S Super B Jetting instructions pdf online and this is interesting. From what they are saying about the symptoms I'm experiencing, it sounds like I need to increase the main jet...

    Street Procedure
    S&S uses what we call “RPMing” method to determine correct
    main jet size. Hard acceleration is evaluated up to the rpm where
    horsepower peaks and begins to taper off and gear shift occurs.
    Main jet that makes engine accelerate strongest or rpm through
    gears quickest is correct.
    1. Warm engine to operating temperature.
    2. Accelerate rapidly through gears noting how quickly and
    smoothly engine reaches rpm level where pull of engine
    begins to fade and gear shift occurs.
    3. If engine backfires in carburetor and sputters or “breaks up”
    and/or dies during acceleration, increase or richen main jet
    size .004 larger and road test again. Note engine
    smoothness and how easily engine reaches rpm level where
    gear shift occurs.
    4. If engine runs flat and sluggish or “blubbers” or will not take
    throttle, decrease or lean main jet size .004 smaller and road
    test again. Note engine smoothness and how easily engine
    reaches rpm level where gear shift occurs.
    5. Continue changing main jets until one is selected that makes
    engine accelerate or rpm through gears most quickly and
    smoothly. Our experience has taught us that a jet about .006
    smaller (leaner) than correct one will make engine “break
    up” and quit. A jet about .006 larger (richer) will make
    engine “blubber” and miss.

  18. #38
    Senior Member

    Content on this page requires a newer version of Adobe Flash Player.

    Get Adobe Flash player


    Join Date
    Sep 2010
    Posts
    12,789

    Default

    A few brief words on the Superbowl ...



    Accelerator pump and float bowl kit improves the performance of S&S Super "B" and "D" carburetors with two cable throttle control.
    Eliminates low end throttle hesitation and improves starting. Some machining to carburetor body is required.

    .../// https://www.vtwinmfg.com/Instructions/35/35-4571.pdf \\\...

    If and when you decide to install a pumper, best to hunt down a og Superbowl, the re-pops are a bit more work to install ...


  19. #39
    Member

    Content on this page requires a newer version of Adobe Flash Player.

    Get Adobe Flash player


    Join Date
    Sep 2015
    Posts
    91

    Default

    Again, not interested in trying a Superbowl. I'm trying to make this carb work as is.

  20. #40
    Senior Member

    Content on this page requires a newer version of Adobe Flash Player.

    Get Adobe Flash player


    Join Date
    Dec 2018
    Posts
    2,107

    Default

    I think what you are describing means you need to increase the intermediate to maybe a .033 or .035. That would suggest that you have a vacuum leak, or the motor has low compression. (The lower the compression, the fatter it has to be.) It is not unusual for smaller motors to need bigger intermediate jets, 900 XLs being a perfect example, often needing the above intermediate jets, even in Super Es to run properly.

    Jim

Share This



Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  

Log in

Log in