Page 1 of 2 12 LastLast
Results 1 to 10 of 13

Thread: 2007 XB12x ULY just drops power at 4grand

  1. #1

    2007 XB12x ULY just drops power at 4grand

    2007 UlY with 33,000 on the clock ran fine last fall over winter did fork seals, intake seals, new injectors and plugs. I took out this spring and when you get on the bike at about 4000RPM the bike just cuts out until you let off the throttle then its fine again till you get on it then the same thing happens. tried a different ECM, ran a ground from the battey to the grd wire on frame, plugged in my Buelltooth and changed the AFV to 100% it was at 85% before, changed the coils and a TPS reset all of these were done in stages trying to figure this problem out!! I am at a loss not sure witch way to go next.. Any help would be great
    Joe

  2. #2
    Senior Member GregoXB's Avatar
    Join Date
    Feb 2012
    Posts
    1,490
    Did you clean and refasten all your ground points? Clean throttle body?

  3. #3
    Senior Member lunaticfringe's Avatar
    Join Date
    Feb 2011
    Location
    AmishLand, PA.
    Posts
    7,517
    joe: when you say "cuts out" i'm assuming here the sensation mirrors turning off kill switch or ignition key. if so that's always electrical. and when it's coincidental with a specific RPM it's almost always harmonics/vibrations related to that RPM. here:
    1-go thru your grounds again. several at steering neck/top triple clamp.....under airbox base-plate at dog-bone support....under seat left frame rail for sub-harness/ecm/negative batt cable.
    2-you mentioned buelltooth. check for any historical fault codes. also data-log and refer to service manual. it shows specifics for TPS voltage output at speeds and settings. if yours is failing the log will show same.
    3-small details like plugs gapped directly??? plug wires perfect???under-seat wiring perfect????and you mentioned "coils". XB's have ONE and ONE coil only. Ulys also notorious for chafing under-seat wiring in vicinity of ecm. check same thoroughly.
    4-lastly if and when you've completed the above check the items that historically cause your problem on 05-07 XB12 models. they are: chafed feed wire going to rear head temp sensor.....chafed wire from harness to behind front pulley cover that is chafing at right cowling-to-muffler support.....rear cylinder injector feed wire chafing.....faulty or burned charging system connector AKA #77 connector also behind front pulley cover.
    report back please!!!
    4-

  4. #4
    Member herwawan's Avatar
    Join Date
    Feb 2018
    Location
    Los Angeles, CA
    Posts
    80
    Hey Joe. It would be great if you could describe the "cuts out" a bit more precisely. I would start with everything wrote above by lunaticfringe - you can then check my post on a similar issue (if I read the "cuts out" in the same way as I had them): https://www.buellxb.com/forum/showth...ll-there/page2

    It was my Cam Position Sensor that was tired and would cause the issue once the engine hot.

    Report back to lunaticfringe and precise the "cuts out"!

  5. #5
    yep did a sonic clean of the throttle body also cleaned all grounds

  6. #6
    I am off duty tomorrow so will start tearing into the grounds again maybe I missed something when I rotated the motor? thanks so much for the starting points

  7. #7
    ok with the Cuts out I will do my best to describe it... if you ride the bike normal it will go past 4000rpm but with a bit of hesitation, when you really get on the throttle it just dies out like there is zero fuel until you let off the throttle then it will kind of run fine again this is from cold or warmed up. you have to completely let off the throttle to get it to keep running if you keep the throttle pegged there is just nothing there

  8. #8
    Senior Member
    Join Date
    Dec 2012
    Location
    Royse City Tx
    Posts
    533
    Fuel Pressure Ok?

  9. #9
    Quote Originally Posted by Tbone View Post
    Fuel Pressure Ok?
    honest I have not checked it and not sure how to. One more thing I need to learn how to do

  10. #10
    Quote Originally Posted by lunaticfringe View Post
    joe: when you say "cuts out" i'm assuming here the sensation mirrors turning off kill switch or ignition key. if so that's always electrical. and when it's coincidental with a specific RPM it's almost always harmonics/vibrations related to that RPM. here:
    1-go thru your grounds again. several at steering neck/top triple clamp.....under airbox base-plate at dog-bone support....under seat left frame rail for sub-harness/ecm/negative batt cable.
    2-you mentioned buelltooth. check for any historical fault codes. also data-log and refer to service manual. it shows specifics for TPS voltage output at speeds and settings. if yours is failing the log will show same.
    3-small details like plugs gapped directly??? plug wires perfect???under-seat wiring perfect????and you mentioned "coils". XB's have ONE and ONE coil only. Ulys also notorious for chafing under-seat wiring in vicinity of ecm. check same thoroughly.
    4-lastly if and when you've completed the above check the items that historically cause your problem on 05-07 XB12 models. they are: chafed feed wire going to rear head temp sensor.....chafed wire from harness to behind front pulley cover that is chafing at right cowling-to-muffler support.....rear cylinder injector feed wire chafing.....faulty or burned charging system connector AKA #77 connector also behind front pulley cover.
    report back please!!!
    4-
    sorry first time posting in the forum, I did reply to you below but wanted to make sure you saw I did reply, I will get the hang of this



Page 1 of 2 12 LastLast

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •