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  1. #1

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    Default Bike only starts with chock on after running

    Bike is a '95 1200 with an S&S Super E, paughco upsweeps, and Dynatek 2000i single fire ignition. Everything else on motor is stock. After riding for about 20 minutes I pulled over to get some gas. After fill up the bike won't start unless I have the choke on about halfway for a few seconds. If I leave the choke off to start, it will just turn over even with a little throttle. I have cleaned the carb and jets thoroughly so I don't think its getting clogged. A bike that is warm shouldn’t need the choke on to start it again so that’s what’s confusing me. Would this have anything to do with idle speed/fuel mixture screws being off? Thanks
    Last edited by dsaav; 05-29-2020 at 1:41 PM.

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    Your problem would suggest it's running lean. Keep in mind, the 'choke' on an S&S Super E is actually an enrichener which opens up an extra fuel circuit to give a more rich mixture for starting. What size low speed jet are you running? Also, you could have an intake leak which isn't showing itself until the bike gets hot. That would lean out your mixture. Need some more info to give anymore advice.

  3. #3

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    Quote Originally Posted by BadMonkeyMW View Post
    Your problem would suggest it's running lean. Keep in mind, the 'choke' on an S&S Super E is actually an enrichener which opens up an extra fuel circuit to give a more rich mixture for starting. What size low speed jet are you running? Also, you could have an intake leak which isn't showing itself until the bike gets hot. That would lean out your mixture. Need some more info to give anymore advice.
    Running a 28 pilot. My intake seals are new I originally had an intake leak but took care of that. How would an intake leak only appear when bike is warm? Thanks

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    Different materials expand at different rates as temperatures rise.
    Some leaks even go away as the bike warms up.

    Throw an eye on vacuum lines too

    Confirm fuel delivery, inspect gas cap to float bowl.

    Heat soak is another possibility.
    do you have the phlolonic spacer installed?

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    Quote Originally Posted by dsaav View Post
    Running a 28 pilot. My intake seals are new I originally had an intake leak but took care of that. How would an intake leak only appear when bike is warm? Thanks
    In my tuning experience, that 28 is likely too small for a 1200cc engine. I would bump it up to a .295 and see how it reacts. It's easy to change the jet and it should tell you if you're headed in the right direction.

    Good advice from Sky to be sure you're running a phenolic spacer between the carb and the intake manifold and also checking that you're not vacuum locking your tank/fuel line when the bike gets hot.

  6. #6

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    The spacer is in. Carb was rebuilt with new gaskets and seals so I don’t think it’s an intake leak. I originally was having fuel delivery issues due to a crappy inline filter that I decided to run without. Seems to run fine but does die at idle if not warmed up thoroughly which might also be due to a small pilot. I’ll try a larger jet and see where that gets me... thanks for the input guys!

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    My guess is you have trash in the tank and carb......

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    Quote Originally Posted by Tattooo View Post
    My guess is you have trash in the tank and carb......
    What makes you think that? That would prove other problems other then just at start up

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    Quote Originally Posted by dsaav View Post
    What makes you think that? That would prove other problems other then just at start up
    Not really......

    Going by what you said..... What makes me think that.... But hell I might be wrong??????

    Quote Originally Posted by dsaav View Post
    After riding for about 20 minutes I pulled over to get some gas. After fill up the bike won't start unless I have the choke on about halfway for a few seconds. If I leave the choke off to start, it will just turn over even with a little throttle.
    You said you cleaned the carb.... But did you do a good job?????? Did you also check the tank??????? Are you running a filter???? If so what does it look like?????

  10. #10

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    Cleaned the carb and tank out thoroughly. Blew all passages out in carb with compressed air. I am running a filter on the petcock and that’s it... I might tear it down again and clean it once more because the tank was a little rust. Although I used some evapo-Rust to clean out all the crap that was in there and drained it good. I am gonna start with a bigger jet and see if that helps... appreciate everyone’s input. I’ll post updates when I get this figured out

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    Quote Originally Posted by dsaav View Post
    I might tear it down again and clean it once more because the tank was a little rust.
    Yep just as I figured............

  12. #12

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    The .295 slow jet was the fix. Thanks badmonkey she’s running smooth and is starting up much better

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    Quote Originally Posted by dsaav View Post
    The .295 slow jet was the fix. Thanks badmonkey she’s running smooth and is starting up much better
    I'm sure it is since you got the trash out of the carb.....

  14. #14

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    Quote Originally Posted by Tattooo View Post
    I'm sure it is since you got the trash out of the carb.....
    Nope no trash in there it was actually super clean since I had already cleaned the tank and carb prior like I said. Just needed a bigger jet. Easy fix

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    Quote Originally Posted by dsaav View Post
    Nope no trash in there it was actually super clean since I had already cleaned the tank and carb prior like I said. Just needed a bigger jet. Easy fix
    So the jet was the reason it started running bad after you stopped to get gas??????? That's what I was responding to........

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    Quote Originally Posted by dsaav View Post
    The .295 slow jet was the fix. Thanks badmonkey she’s running smooth and is starting up much better
    Excellent. Glad to help and glad she's running right for you now. Ride safe.

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