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  1. #1

    Join Date
    Sep 2015
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    7

    Default S&S Super E Carb Tuning help

    Hey all,

    I have a jetting question. I have a 86 HD Softail (FXST) with the 1340 Evo. It has the S&S super E carb and intake on it and I think it has thunderhead exhaust on it. As far as I know, the engine is stock as it was a show bike and has 5200 on the clock. Long story short, she runs OK. when its warmed up, I can rev it up a bit and she'll spit a flame out the exhaust for the rear cylinder which tells me the intermediate jet is a little rich (jet is a 295 I think). After riding it a bit and getting it warmed up after a ride, it seems to stumble and pop a bit and it seems like its too lean. The top end seems fine. There is a 68 main jet in there now. It does have new plugs and a recent oil change. I think the accelerator pump is about 1.5 to 2 turns out and the mixture screw is somewhere around 3 out. I'm also at 68 feet above sea level. I'm curious as to what other people are running for jets or to see if anyone else can help me out to get it running better rather than me having to take it to the dealership and running it on a dyno.

    This isn't my first go around with carbs, but for some reason, there isn't much posted about jetting and tuning the carb and this one is getting to me. Everything from S&S seems kinda generic. Any help is appreciated.

    Thanks.

  2. #2
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    If yer running a dual fire ignition, and the mix is way fat. you'll see that flame. Timing can affect this as well.
    Did you read the part about 1-1/2 turns out on the mix is what your looking for? Otherwise time to swap the intermediate jet.
    Are you looking at the plugs? Post a pic maybe, you can tell a lot by the plugs even without a plug chop.
    Checking for intake leaks? Missing the pump tower o-ring? Pushrods adjusted? Compression good? In other words is everything in good working order?
    Bump up the main jet till power falls off and go back one step. 68 at almost sea level for an 80" is probably lean, I'd have started with a 72...

    What seems to confuse people is that the intermediate jet is not an idle jet. The mix screw controls idle fuel (fed by the I-Jet) and the I-Jet takes over fully once the throttle plate opens a bit...
    http://www.sscycle.com/download_file/385/184/

  3. #3
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    Everything Sky said........ If I were you, I would start with checking for intake leak . Check it when its warm if that's when the sputtering/popping occurs.

    If there is no intake leak, I would up my main jet to 72 and intermediate to a 31. and see if that gets your mixture screw in the right neighborhood of 1.5 turns out

  4. #4

    Join Date
    Sep 2015
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    Well, i guess it may be a timing issue. Adjusting the carb didnt help any. When i get more time, i'll try and retard it a bit and see what i come up with. Thanks for the input.

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    I have a 1980 shovel 86 ci , super e shorty carb. I have a 68 main and a 29.5 slow jet. It runs fine. it ran bad with any jets higher

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  7. #7
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    Tune the low speed jet with the accelerator pump completely OFF/DISENGAGED. If you dont it will cause issues, like improper jetting. most people set the pump 2 turns then try to tune it, all it does is mask the issues.

  8. #8

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    Sep 2015
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    I have already watched the videos before they were posted here. The accelerator pump was off before it was tuned. Because it is an intermittent low end problem and it had been tuned using various jets, I'm going to look into either a timing or ignition problem. I'll shoot for the timing first before i go to a single fire ignition. It could be as simple as the timing plate is starting to go bad and I'll test that as well once i get home this weekend. I'll let you know how it turns out.

  9. #9
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    Intake leak / exhaust leak.

  10. #10

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    Sep 2015
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    So it does have a Crane Cams single fire ignition. The spark advance was turned all the way up, the rev limit was all the way down to 5k and the rear cylinder was at -5 degrees. Not knowing the internals of the engine, I might have to run premium and adjust the spark advance about 3/4 of the way up. I'll have to adjust the rear cylinder once she's been tinkered with.

  11. #11
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    Are you running voes

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