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Thread: rt missing under acceleration

  1. #1
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    rt missing under acceleration

    2015 RT wethead 40,000 miles just started skipping under acceleration any suggestions?

  2. #2
    TravelsWithBarley.com
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    Cracked plug insulator..?
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    Liaison 20774's Avatar
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    Any recent maintenance work?
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    Registered User cap's Avatar
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    Quote Originally Posted by woody99 View Post
    2015 RT wethead 40,000 miles just started skipping under acceleration any suggestions?
    Fuel, air, spark. Those are the factors in combustion. So, you can look for a blockage in your air filter, replace your sparkplugs and fuel filter. If none of that cures it, then let us know.

    cap

  5. #5
    Addicted to curves azgman's Avatar
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    Can you elaborate on what you think "skipping" is? A wethead does not have a fuel filter BTW.
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  6. #6
    Registered User cap's Avatar
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    Quote Originally Posted by azgman View Post
    ...A wethead does not have a fuel filter BTW.
    We have a "filter screen" P/N 16 14 8 543 001. It is attached to the input of the fuel pump inside the gas tank. If you are suggesting that this is an unlikely cause of the "missing," then I would agree. But I have experienced load-based fuel starvation in other engines that was caused by a partial blockage of a fuel filter. So, it's possible.

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  7. #7
    Registered User stooie's Avatar
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    My first guess would be something in the ignition system. Being in a marine salt air environment can cause all sorts of problems.

    1. Do you have a GS-911 or other tool to see if there are any fault codes? If not, it might be worth having the dealer check for codes.

    Whoops! I just looked at a map of Hawaii. I guess getting to the dealer is a good deal more complicated than cruising three exits down the freeway.

    2. Are the spark plugs relatively new? What do the electrodes look like?

    3. Are the spark plug wires the originals? A plug coil might be on its way out.

    Good luck with it! When it gets resolved please report back on what you found.
    Last edited by stooie; 12-01-2020 at 08:15 PM.
    Bob Stewart
    Salem, OR

    2018 RT

  8. #8
    Registered User alegerlotz's Avatar
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    Quote Originally Posted by stooie View Post
    ...
    3. Are the spark plug wires the originals? A plug coil might be on its way out.
    The coils mount directly to the spark plugs themselves. There are no "Spark Plug Wires" in the traditional sense of something that goes between the coils and the plugs. The wires going to the coils are part of the overall wiring harness.

    The coils themselves could be an issue, however. These have been known to fail, especially when spark plugs are not changed when needed and the electrodes get flat on the sides (they start off round). The flattened sides on the center electrode increases the gap and this puts more stress on the coils.
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  9. #9
    Registered User cap's Avatar
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    Quote Originally Posted by alegerlotz View Post
    The coils ..have been known to fail...
    Does anyone have experience with the failure mode of our wethead coils? I had a dual-spark R1150RT, and I had multiple coil failures. On that bike, when a coil failed, it failed hard -- that is, it stopped working altogether. And the result was much like the OP described, rough running. But that was because there was a redundant spark. If there had been only one spark, and the coil failed, then the engine would just barely run.

    That dual-spark was a cool bike. I once had both coils fail during the same long trip, and the bike ran OK. It was a little rough, and so when I got home, I went through the coil-diagnosis protocol of disconnecting one coil at a time while the engine was idling. I disconnected the first coil, and it didn't make a difference, and I thought "must be a bad coil, but I'll check the other side anyway." So, I disconnected the other one and that one didn't make any difference either. Amazing what a difference there is when you have a new pair of working stick-coils.

  10. #10
    Registered User r0ckrat's Avatar
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    Not with COP (Coil on Plug), but I know that it is possible for a coil to fail in other ways. On a 91 318i I had one coil in the pack develop a crack in the housing, which resulted in a short to the frame *under load*. It would sputter on 1 cyl when trying to accel up a specific hill, but otherwise be fine...

  11. #11
    Quote Originally Posted by woody99 View Post
    2015 RT wethead 40,000 miles just started skipping under acceleration any suggestions?
    Missing or skipping under load is usually some kind of fueling issue. Could also be with the spark. With issues like this, start with the simplest easiest things to try.

    1. You may have some water in the fuel tank. Try running a some fuel treatment through the tank and see if that helps. The treatment will help to get the water out.
    2. Check the coils and spark plugs. May sure they are tight. I have had a spark plug back itself out once.
    3. Change the spark plugs. Could be that one is going bad.
    4. Check all the electrical connections to the throttle bodies, etc. Could be that one wasn't inserted completely and may be slightly loose.
    5. As was mentioned earlier, check the air filter to make sure it's not blocked.

    Those are some simple things you can try without having to spend very much money and without having to tear too deeply into the bike.
    Scott Taranovich
    McKinney, Texas
    2019 R1250RT

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