running just a little rich

Discussion in 'Engine, Fuel and Exhaust' started by HOLY DIVER, Jul 30, 2013.

  1. HOLY DIVER

    HOLY DIVER Junior Member

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    my deuce is running just a little rich i'm not going though spark plugs like hot cakes or anything,just on the rich side i've adjusted the fuel mixture screw can't get it worked out i'm thinking its the jetting.my main concern is this is a new engine will running a touch rich be harmful to it during break in? can't get it on the dyno to tune it correctly until i hit the 1000 mile mark.got 450 miles logged so far on the new stoker motor
     
  2. Slo-Ryd

    Slo-Ryd Junior Member Contributor

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    A little rich is fine and better than being a little lean, imo. Extremely rich and you might run the risk of cylinder wash but i think you should be fine. Doubt you're dumping that much raw fuel into the motor though. Just my thoughts.
    [​IMG]
     
  3. dbmg

    dbmg Experienced Member

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    How is over all performance or is your thought driven by pulling and looking at the plugs?????
     
  4. Jeff Klarich

    Jeff Klarich Well-Known Member Contributor

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    +1 on running a little richer, Harleys seem to run to lean from the factory. Unless your dumping to much fuel you should be fine.
     
  5. dolt

    dolt Senior Member Contributor

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    More information please. What is the build? CV or Mik carb? How is the carb currently jetted? What symptoms make you think she's running rich?

    The A/F screw is for idle and transition from idle to pilot/slow circuit. Depending on the motor configuration, exhaust, etc., that screw should be somewhere about 3 turns out, give or take. There is no fixed number of turns, every motor is different. When you bottom the A/F screw out, the motor should idle rough, stumble and ususally will die. If not, the pilot jet is too big. That's the first step to jetting and it needs to be done with the motor at operating temps.

    The A/F screw has an o-ring at the tip; those can fall of/out and get lost; make sure the o-ring is in place. It may not come out of the threaded A/F screw bore as they will often stick in the bore.

    Back the A/F screw out, slowly, like 1/2 turn at at time and give the motor a chance to adjust. Go out say 4 turns and back in 3 turns the same way. Listen to the exhaust and watch the tach and motor movement. At some point between 1 and 4 turns there will be a "happy" place, once you find it, note how many turns of bottom that happy place is and write it down. You are now ready to move to mid range tuning, i.e., pilot and needle.
     
  6. HOLY DIVER

    HOLY DIVER Junior Member

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    ok more info:i'll give you all i have on hand at the moment.
    bike was stage 1 when i got it carb jet,heavy breather,pipes and it ran like a top until the crankshaft went south with .032 run out in it.
    engine rebuild/upgrade:SE stroker crank with new HD pistons which took it to 96ci
    cams installed now are S&S 510 grind
    my indy mechanic moved the needle up one for fear of it not getting enough fuel during break in.bike runs strong much much more power but i smell fuel and its not leaking.if i try and go down the road in 3rd gear at 30mph just barley giving it any gas it sounds like a race car with a extremely high lift cam,when i twist the throttle from this point it does not stumble at all just pours the HP on.but over all its not running smooth S&S 510 grind cams are not aggressive enough to cause this(my thinking could be wrong)
    2003 deuce with a CV carb
     
  7. dolt

    dolt Senior Member Contributor

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    I would drop the needle back to the original position and start the tuning process from scratch. Adjust A/F screw first, then pilot/needle and then main jet.
     
  8. doctor727

    doctor727 Active Member

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    Have read all the posts and have a question. In your opinion, what is "not running smooth" mean? I think you said it was rebuilt into a 96 with cams. In my experience, a stroker moter will not run the same as a stock motor. Is it unbearable at speed? you stated it "pours on the HP with a roll of the throttle". If it were mine, I would keep checking for any fuel leaks, I would check the fuel mileage and ride it. I don't think you have a problem. I don't think I would start rejetting just now. Just my .02 :s
     
  9. HOLY DIVER

    HOLY DIVER Junior Member

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    carburators are not my thing,i'm going to deal with it until break in is complete and then have it dyno tuned with a thunderslide kit if it fouls a plug i'll start to worry
    fuel mileage is not good at all i might be getting 29mpg
     
  10. dolt

    dolt Senior Member Contributor

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    One last suggestion to make an effort to tune the carb. 29mpg indicates a rich condition and if too rich, you could be washing the cylinder walls which will not help the break in process.