2011 Shadow Phantom 3,500 miles - Power loss, hesitant start

    • 3 posts
    November 23, 2018 2:41 PM PST

    I bought this bike this past summer with 2,700 miles on it after it had been sitting for some time. Took her on some hour long rides and used as my daily for a good 2-3 months and put 700 miles. Then, one day before I got on the turnpike I filled up at a Sunoco with 93 octane. Then, 30 minutes into my ride, all of a sudden she lost a significant amount of power. one minute I was cruising with traffic, the next I couldn't go faster than 40 mph while pinned in 5th. The motor sounded regular and there was nothing unusual. It was like this for the rest of my ride home which was another 45 minutes.

    This didn't happen again immediately the next time I rode, but it happened off an on for a day or so. Now it is all the time.

    Now, when I pull out from a stop in 1st gear, i give it throttle and it doesn't go anywhere but sounds like its about to stall. the more throttle I give it the worse it gets. I have to shake the throttle quickly, increasing then decreasing then increasing again in order to get it moving, but even then it has surges of power loss. Shifting to second sounds like it wants to stall, so I have to shake the throttle again.

    I let it sit for a couple of weeks and used my car to get to work until i had some time to look into this. Next time i started it she stalled right away. took 3 tries to get her running, and then her idle was off. you can hear it sputtering and sounds like it will stall.

    Heres what i checked:
    - drained gas and ran seafoam through it with fresh gas
    - all 4 spark plugs look good, I'm assuming the boots are fine as well, but i will replace the plugs this weekend anyway
    - both pipes heat up quickly and you can feel that the exhaust is coming out from both of them evenly
    - the air box is all good
    - checked all fuses
    - I can hear the fuel pump prime itself fine when I turn it on
    - throttle positioning sensor works as it should
    - while running some tests I turned it on and off a bunch of times, the battery died very fast so I charged it but it wouldn't hold a charge. I replaced the battery but that didn't change anything
    - cleaned fuel pump filter with fresh gas and inspected the connection
    - all relays work as they should including fuel cut off relay

    Next, I plan to check the spray pattern of the injectors and measure how much fuel it pumps out. I'm also aware that this bike never had its bank angle sensor replaced, which was recalled. But, since it has a mind of its own when i pull out at a stop sign or red light, i'd rather not ride it all the way to the dealership.

    Any thoughts on what to inspect?

    Thanks

    • Moderator
    • 19004 posts
    November 24, 2018 6:54 AM PST

    Looks like you've been pretty thorough. I'd suspect what ever is controlling the injectors.

    • 3 posts
    November 25, 2018 12:28 PM PST

    I believe I found the culprit. I decided to check the spark plugs again. I checked them when this first started and they were fine, now it has been a few months and they're black. My bike's been running very rich, but only since this started to happen. So, I replaced the plugs, pulled the air filter off and the bike ran great. The air filter looks ok though, it's not soaked or anything, and with around 3,500 miles on her, I'd be surprised if the filter is the only issue. With Vance and Hines pipes on her, there's no opening for an O2 sensor. I haven't found the eliminator yet if there is one. Next thing I'll do is check the mass air flow (iat) sensor.

    Any other suggestions on why it may not be getting enough air at all speeds and throttle positions?

    • 3006 posts
    December 4, 2018 2:13 PM PST

    The only things I can think of #1 isn't the shadow supposed to run on regular? premium gas will cause the motor to run poorer than normal,or at least it does on my Honda Vtx1300..#2 Perhaps the fuel map on the ECM needs to be adjusted to allow for the aftermarket pipes,the airfilter has been changed to aftermarket?

    Also make sure the fuel pump is delivering the proper fuel flow to the injectors,just because you hear it does not mean it is working properly.I went thru 2 fuel pumps over 12 years,before I took the fuel pump off and switched it to gravity fed,yet my ride has a carb no EFI.,not sure if you can do that w/your ride.

    stay safe & enjoy the ride

    • 3 posts
    April 6, 2019 9:31 AM PDT

    SOLVED
    The issue was with the OEM Honda air filter. When this issue first started, one of the first things I did was check the plugs. Since the plugs looked great, I didn't think it was a fuel-air ratio problem. After I had kept riding it on and off for a few weeks, I checked the plugs again and they were black. Since it was getting too much fuel/not enough air, I pull the air filter off, replaced the cover, and rode it around. I'm not sure why the air filter failed, but the bike performed great without it. I replaced the air filter with a K&N and the bike runs fine now.