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03 Chopper spitting, coughing and running on 1 cyl

Discussion in 'Help Wanted' started by 2003BDChopper, Apr 20, 2016.

  1. 2003BDChopper

    2003BDChopper Member

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    She's been coughing and spitting and been giving me greaf since I got her. Once I found 2 open holes, one on top of the carb and one on top of the intake and blocked them, I helped alot. Ive also ordered new intake to head gaskets. I found it was leaking after I sprayed some startgas around the seal. Hopefully that will make it run even better.
    Put all that aside, and have a new problem. Lately its been goin back and forth running on 1 or 2 cylinders. Couching and twitching like crazy. Ive been through 2 coils, different sparkplug wires, new sparkplugs etc. The strange thing is she always runs fine right after startup. And I can do about 10-15 kilometers before she starts actin up.. And if I turn the throttle all the way back once or twice and let her rip, she will start goin on 1 cyl much faster then if I ride her gentle..
    One more thing, when running on 1 cylinder, the more throttle I give the more she start running back on 2. Not clean at all, and I have to shift down and get the revs up to force her running on both, but she does.

    Isnt this typically a problem with the EHC?
     
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  2. fuelman97

    fuelman97 Member

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    Startgas is that like starting fluid? If it is, that would be the last thing I would use. I like to use a propane torch "not lit" to chase vacume leaks. Vacume leaks can make an engine run like trash. Your carburator requires a good tight intake trac to atomize fuel properly. I'll try to keep it simple At Full throttle your engine runs better because of low vacume,and low air speed. Anyway this how I diagnose a leak. With the bike running I go around all flanges,ports and thottle shaft with an unlit propane torch if there is a leak present. The propane will be pulled into the leak and compensate the lean condition. Causing the bike to run smoother
     
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  3. fuelman97

    fuelman97 Member

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  4. fuelman97

    fuelman97 Member

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    As far as the two holes on top of the carb and intake, use a wire tie on the plug to prevent them from coming off when the motor cough's
     
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  5. 2003BDChopper

    2003BDChopper Member

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    Thanks. Propan might be better. But using starting fluid around the port made the engine rev. So I know its leaking. Hopefully new gaskets will help.
    However, the leak is not the problem right now. Its the bike running on 1 cylinder..
     
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  6. 2003BDChopper

    2003BDChopper Member

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    Yea i have.They should be alright.
     
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  7. fuelman97

    fuelman97 Member

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    Does the engine have compression releases? Could one of them be stuck open?
     
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  8. 2003BDChopper

    2003BDChopper Member

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    Yep, got em. Havent even thought about that....
     
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  9. 2003BDChopper

    2003BDChopper Member

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    They both open and close properly. So must be something else...
     
  10. HMAN

    HMAN Well-Known Member
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    I know on my Pit from time to time the rear plug wire will ease off the coil side just enough to cause a rear cylinder drop out. I can reach in and feel it click back into place and the Dog runs like a champ again. Just my .02
     
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  11. francoblay1

    francoblay1 The Spaniard

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    zip tie em!

    [​IMG]
     
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  12. HMAN

    HMAN Well-Known Member
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    Thought of that, but prolly ought to just replace the wires first. Not sure how long they have been on the bike? Maybe since 04? Lol....
     
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  13. Sven

    Sven Well-Known Member

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    I would first eliminate compression of both cylinders so there is no question I am chasing my tail for spark or fuel. I would then setup a timing light to said dead cylinder wire and if it keeps sparking, the timing light will show it = Spark drop? Why? Seems like the other cylinder has no problem taking fuel from the carb, no problem of a single coil sparking the other cylinder, not fuel, not compression, has to be spark; you'd think.
     
  14. BadDawg Bill

    BadDawg Bill Well-Known Member

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    You have to start with first things first. Replace the intake gaskets and rebuild the carb. Make sure they are sealed and the float is set right. Second, You may have a weak compression release on the one cyl that opens when hot. I'd replace both of them. If that doesn't fix it then I'd replace the ign system. Get a Crane or other top unit or replace the Thunder one.

    It's hard to pin point the problem when you have many issues.
     
    #14 BadDawg Bill, Apr 21, 2016
    Last edited: Apr 21, 2016
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  15. Srodden

    Srodden Well-Known Member
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    Exactly fix what you know is wrong then go forward. It could be all of the issue.
     
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  16. 2003BDChopper

    2003BDChopper Member

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    Getting the intake to head gaskets tomorrow. That should fix my leak problem. Carb rebuilt last year. Also spent some time setting up the carb With the right jet size. Plugs were white when i bought, so was running lean. After riding 2-3 months the sparkplugs look Perfect colourwise.. But the carb probably needs another tweak after i fix the leak though..
    Compression release open and Close. But when theyre propper hot, who knows. Havent tested..

    Guess i`ll take fix one thing at a time. Eliminate as much as possible before i start lookin at wireplus kit etc...

    Thanks for inputs :)
     
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  17. 2003BDChopper

    2003BDChopper Member

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    Looks like the compression release is working fine, even when hot. And found out its the front cylinder dying on me.

    With all the freagin wires on this bike which I don't need half of,i really wanne tear it all out. Get rid of the ehc, thunderheart ignition, all of it. And then set up a complete new harness with new ignition with the module built in. Ive looked at Ultima ignition http://www.demonscycle.com/high-per...ignition-module-for-harley-davidson-3911.html
    And Harness http://www.demonscycle.com/ultima-complete-electronic-wiring-harness-system-for-harley-davidson.html

    Hopefully it`ll fix the problems I have with ignition, and give me a new clean harness without the ehc and bundle of wires under my seat.

    What do you think guys?
     
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  18. BadDawg Bill

    BadDawg Bill Well-Known Member

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    I think it's a GREAT idea but you will need new bars and controls too. Go for it!
     
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  19. fuelman97

    fuelman97 Member

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    Here an idea on the compression release swap them and if the front still acting up it not the release
     
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  20. FrankBDPS

    FrankBDPS Well-Known Member
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    Bill, on an 03 do the handle bars neck down to 1inch got Harley style controls? I don't understand why he has so many wires. His Thunderheart should be the same as mine meaning old school and not complicated. I changed out my ignition with out rewiring the whole bike. You just need to move the hot wire to the key switch. It's no big deal.
     

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