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'03 Fat Boy Running Rich

Discussion in 'Motorcycle Tech Talk' started by tl1023, Dec 6, 2015.

  1. tl1023

    tl1023 Member

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    Haven't ridden much this year and bike wouldn't idle when cranked recently. Ordered deluxe tuning kit and installed yesterday with no issues. Bike has stage one air intake and Rinehart exhaust and recommended jets were used along with EZ-just mixture screw, EZ idle adj screw, velocity needle and slide spring. Engine cranked right up but after a few minutes began running rich and would not run at all unless throttle was opened up. Tried adjusting mixture but was still rich even after turning mixture screw all in. Ideas??
  2. hotroadking

    hotroadking Super Moderator Staff Member

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    Pilot jet is too large drop it down one size
    Marc1340 likes this.
  3. Marc1340

    Marc1340 Active Member

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    Check the Float level. google specs for degrees, on the norm 15 to 18 degrees
  4. bambidee

    bambidee Active Member

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    Both of the above could be, float level would most likely cause a hard start/ rich idle from flooding all the time, esp warm. What was the pilot before and now? Turning the mix screw all the way in should lean it out at idle unless you went huge on pilot but cause other drivability issues. might even be some shzitt that floated to another area when you cleaned the carb. We all most likely agree start with the carb again(SIGH)Do you think the original issue was rich or lean?
  5. tl1023

    tl1023 Member

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    Pulled the carb off again today, installed smaller pilot and, rechecked other parts, and installed. Engine started immediately but after a minute, began running very rich again and mixture screw had zero effect. Would only run when throttle was held open about quarter of full. Original problem was bike wouldn't start at all and I found the pilot to be clogged when I was installing CV kit. I didn't bother float and it appears to work fine; however, I don't have a gauge to check degrees. Appreciate your ideas-----may have to haul it to pro. I'm pretty accomplished mechanic on many types of engines but not much experience on scooters.
  6. Marc1340

    Marc1340 Active Member

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    Google the degrees of the float, I think it is 15 degrees and cut a piece of wood at 15 and lay it on it should lay straight up and down make she is not leaking either that will also make it sink when running just a bit, the bowls are real cheap. A small amount of bend to the tab will make the adjustment.
    http://www.dansmc.com/carbs.htm
    Just one place, there is a number of places on the web for adjusting the CV Carbs.
    Don't forget the needle valve, if you are replacing the float replace the Valve

    Just a note watch out for the plastic fuel inlet, as they age they get brittle and crack easy and replacement is a small project to do. Compressed air will be your friend throughout this project to spray and clean all the nooks and cranies Keep us advised
  7. bambidee

    bambidee Active Member

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    never tried this but if the fuel level is to high be it float or needle/ seat issue can you take a pair of needle nose pliers and pinch off the fuel, if so when the engine uses the excess fuel it would idle for a short period. any way the choke/ enrichner is fudged up from the removal and rebuild?
  8. kenfuzed

    kenfuzed Administrator Staff Member

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    Certainly sounds like float level to me. The float may be set fine but if the needle valve is worn, stuck, or has debris under it this will allow the bowl to continue filling until you reach a flooded condition. That would account for the need to open the throttle to keep it running, thus using the excess fuel. Jetting probably wouldn't flood the carb gradually like that, you would be running rich immediately upon starting.
  9. bambidee

    bambidee Active Member

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    With vac control on petcock fuel level sounds like the most likely culprit.
  10. tl1023

    tl1023 Member

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    Ordered new needle for float and smaller pilot jets from CV. Installed and, while better, engine is still running rich after it warms up with choke off. The tube running from petcock to carb appears fine. Any more ideas?
  11. hotroadking

    hotroadking Super Moderator Staff Member

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    Did you adjust the idle mix screw


    Sent from my iPhone using Tapatalk
  12. tl1023

    tl1023 Member

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    Yep. Even adjusted all the way in, still rich.
  13. hotroadking

    hotroadking Super Moderator Staff Member

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    That's what I was thinking, if you can run it in with no idle change then the pilot jet is too big, drop it one size, warm up set throttle at 1500 rpm and adjust also turn that screw in lightly so you don't damage the carb
    Last edited: Jan 20, 2016

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