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Thread: Bucking at freeway speed

  1. #1
    apriliaforum newb
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    Bucking at freeway speed

    So, I took the bike out today after a nice ride last night. Ran great. Stopped at a buddies house for a few and headed home. A little more than 1/2 way home on the freeway it starts bucking and flashing the EFI or is it EF1 light. pretty sure its EFI. Anyway, I exit and it dies as Im downshifting on the ramp. Immediately downshift and compression start it before I lose momentum, dash resets, and I ride the mile or so home completely without issue. Once I got home I let it sit a bit then went out and restarted it. started right up first try no choke. Im going to bring my multimeter home from work tomorrow and get a reading off the battery anyway, but wanted to see if there was anywhere else that I should be looking? Sidestand switch?

  2. #2
    apriliaforum expert kzmille's Avatar
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    When EFI flashes it generally means that the self diagnostic system has detected a fault. There is a pair of wires with a barrel connector under the right side cover that will put the system into diagnostic mode and show any detected faults. The weak point of this system is that it does not have the ability to remember codes. When the key is turned off the code is lost. So if you get this EFI flashing again connect the wires before turning the key off and see if you get a code displayed on the right side of the dash. Fault codes are two digit numbers. If no codes are detected the display shows the Throttle Position Sensor (TPS) reading as -1, 0, or 1. 0 and 1 are normal readings, -1 always means the TPS needs to be adjusted.

    The are occasionally odd conditions where EFI will flash on occasion but no faults codes come up. Sometimes this can be caused by loose connectors or a bad ECU.

    The side stand switch can cause intermittent cutting out but will not cause a fault or EFI flashing. The side stand switch is either opened or closed. A bad switch will go open circuit intermittently. Since open and closed are both normal conditions of the switch the system cannot detect a fault with the switch.

  3. #3
    apriliaforum expert
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    Clean and tighten your battery connections and then make sure your battery is fully charged and your charging system is working properly. That's the first thing to look at if you suspect an electrical issue.
    Hoosier, not hoser.
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  4. #4
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    Checked the battery and connections, clean and tight. Read a steady 13 volts. I guess I'll just keep an eye on it and try to pull a code if it happens again.

  5. #5
    apriliaforum expert kzmille's Avatar
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    You should check the voltage at the battery with the engine running. The display is not very accurate. 13 volts at the battery would indicate a low charging output.

  6. #6
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    I read the voltage at the battery with a DMM not the display, I know that to be inaccurate. I read it again and saw 14.1 volts at idle.

  7. #7
    apriliaforum expert kzmille's Avatar
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    14.1 is a good number.
    Last edited by kzmille; 04-25-2012 at 11:32 PM.

  8. #8
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    KZ, how come you edited out the part about the relay possibly being bad? Did you rethink and no longer think that a possibility? I was looking at replacing it with this http://www.ebay.com/itm/Starter-sole...item35bb5515aa

    unless there is a better solution?

  9. #9
    apriliaforum expert kzmille's Avatar
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    I had this thread confused with another. The relay comment did not apply to this thread.

    I thought this was about "bucking at freeway speed" and EFI flashing. Are you having starting problems as well?

  10. #10
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    Nope, no starting problems whatsoever. I did however have another issue that I posted about here: http://www.apriliaforum.com/forums/s...r-while-riding

    I have since replaced the ignition switch located in the top triple and have had no similar issues since. Think it could be related?

  11. #11
    apriliaforum expert kzmille's Avatar
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    Hard to say. Did you ever connect the diagnostic wires?

  12. #12
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    Only time it has ever happened was the day I posted. I never got any EFI light with the issue I linked. You said the cluster wont store the code so I didn't bother connecting the diagnostic wires. I haven't had a chance to go back out on it yet either. Tomorrow I was planning on lifting the tank and checking the airbox, plugs, and wires.

  13. #13
    apriliaforum expert kzmille's Avatar
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    It holds the code as long as the key is on. Since the problem is intermittent it's worth connecting the wires periodically to see if anything is there but you have to connect them before you turn the key off.

  14. #14
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    Pulled up the tank and saw a gap in the airbox gasket, fixed that. Also cleaned the super dirty air filter.

    Happened again...... Connected the diagnostic wires and got code 1? Im assuming thats gonna be something like a misfire. Off to search, but if someone could link me to where codes are defined that would be awesome.

    Reread KZs original reply and it seems like that would just be the position of the TPS? And that it is a normal reading.

    Given the condition of the air filter I'm now thinking it might just be time for new plugs? Is it best to just stick with the factory recommendation?
    Last edited by rsvwanted; 04-30-2012 at 08:57 PM.

  15. #15
    Honest always, feared often Micah / AF1 Racing's Avatar
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    I like to go up a heat range on the street ridden V990's to DCPR8E from the stock DCPR9E plug set. They stay cleaner for longer. If you trackday the bike use the 9 heat range plugs.
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