04 Vtec popping sound under tank

Discussion in 'Mechanics Garage' started by gingerwinger, Nov 17, 2016.

  1. gingerwinger

    gingerwinger New Member

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    Hi all

    I have developed a popping sound (like popcorn popping) when I rev the engine slightly and when the bike slows down. Doesn't make a sound out of the exhaust but sounds as if it's coming from under the tank area.

    I have tried recording it but it doesn't pic it up due to the engine noise but it is noticeable to the ear.

    The engine sounds rough in my opinion at low revs and is hesitant if revs are slowly increased. I'm guessing there's a problem but before I strip it all down and have a look I thought I would ask your opinion as to where to look first.

    Cheers guys/gals, love this site :)
     
  2. gingerwinger

    gingerwinger New Member

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    Ok I've managed to get a video of the sound as I removed the air filter.

    Any ideas to the popping and clicking sound will be greatly received.

    https://youtu.be/uegbKYuPoZQ
     
  3. Lint

    Lint Member

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    It's totally normal. It's your PAIR valve opening. It's been there the whole time. Disconnect it and it will go away. Or leave it, either way, nothing to concern yourself with.
     
  4. John451

    John451 Member

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    If the pop is directly under the tank it could just be your flapper valve on your airbox, if so is common issue. If you've also lost power with some backfire under engine braking then could be your pair valve gummed open.
     
  5. gingerwinger

    gingerwinger New Member

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    Thanks guys for taking the time to help.

    I was thinking of doing the PAIR Valve, flapper and snorkel mods to see if that makes a difference. Not sure if it effects the MOT in the UK for emissions.

    The ride is bloody terrible. The acceleration is snatchy and when taking off the throttle its like hitting a brick wall it stops so quick. Sadly I'm not enjoying at the bike at the moment but determined to try and find out what is wrong.

    I have been thinking of taking out the injectors and trying to clean them using it for work I'm stuck if I make an error.
     
  6. B6_Dolphin

    B6_Dolphin New Member

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  7. CandyRedRC46

    CandyRedRC46 Member

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    pair valves/snorkel/flapper delete
    02 eliminators
    ultrasonic cleaning for the fuel injectors
    starter valve sync
    new spark plugs/air filter/fuel filter

    Will make a big improvement. If you still are not happy, tuning with Rapid Bike, Bazzaz or Power commander will make the bike buttery smooth.
     
  8. gingerwinger

    gingerwinger New Member

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  9. gingerwinger

    gingerwinger New Member

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    O2 eliminators? what are those? I know what an O2 sensor is but what eliminates them?

    I have done a sync and was good for a few rides but then went crap again shortly after. Replaced sparks so will re-sync the starter valves again this weekend.

    Surely Honda can make a bike ride smooth with all this tech as why bother? I know emissions is an issue but you need to have a bike that ride able! May go make to my Honda Varadero 125 lol No issues with that :)
     
  10. CandyRedRC46

    CandyRedRC46 Member

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    Basically the o2 sensors on the VFR800 from 2000-2013 are narrow band and only used during light/steady state throttle, to push the air/fuel ratio to the absolute lean limit, for mpgs and emissions reasons. Anytime you roll on the throttle the o2 sensors are disabled and the fuel injection runs open loop, but hold the throttle steady and the o2 sensors are brought back into the equation and the fuel injection goes closed loop and leans the mixture out to the limit and you feel lean surging. As you can imagine this makes holding a steady speed difficult with all this transitioning from open/closed loop and afr bouncing around all over the place. This also makes tuning the correct AFR impossible as the ECU will be trying to bring the AFR over 14:1 while the tuner is aiming for 13.2:1, so power commanders/bazzaz and Rapid Bike come with o2 eliminators like these:

    http://www.ebay.co.uk/itm/Oxygen-la...kit-Honda-VFR-800-F-V-tec-00-on-/261335531428

    You can make your own with 330 ohm resistors or just buy them or a fuel tuner that should come with them...
     
  11. gingerwinger

    gingerwinger New Member

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    Thank you CandyRedRC46 for the explanation. Does it effect the emissions disabling the O2 sensors for testing purposes? I'm guessing I'd have to put everything back to stock?
     
  12. CandyRedRC46

    CandyRedRC46 Member

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    I honestly don't have a clue about UK MOT.

    Sent from my Nexus 6 using Tapatalk
     
  13. NorcalBoy

    NorcalBoy Member

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    The only way to tell definitively is if you test the exhaust with an exhaust analyzer...typically associated with dyno time, but you might be able to find a place to stuff a probe in your exhaust and tell you what the emissions readings are.....Euro 4, uggggh. Love the UK, just not a fan of all the Euro regs.
     
  14. Diving Pete

    Diving Pete Member

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    I'm sure that motorcycles don't have to worry about emissions in the U.K. Mot test.

    In fact on the gov website:

    The only vehicles that don’t have an emissions test as part of the MOT are:

    vehicles with less than 4 wheels
    those with 2-stroke engines
    hybrid vehicles
    quadricycles
     
  15. gingerwinger

    gingerwinger New Member

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    Update...

    I disconnected the PAIR valve and Flapper, re-synchronised the starter valves and so far so good! Sun was pointing straight in my eyes on the test run so couldn't open it up to have a proper test as couldn't see properly. Slow speed was way better so looking to do the O2 sensor block too. Not going to do the Snorkel mod as living in the UK rain is common and I've hear its not good to remove it is in a wet climate.

    Thank you all for your comments, without you I would have divorced the bike, now I'm beginning to fall in love again lol
     
  16. CandyRedRC46

    CandyRedRC46 Member

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    Might as well do the snorkel, since you have the flapper defaulted open, which is basically the same. I wouldn't worry about the snorkel. I think it's more of a sound reduction component than a rain/debris protection component.

    Sent from my Nexus 6 using Tapatalk
     
  17. gingerwinger

    gingerwinger New Member

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    I was thinking its unlikely for water to get through but have seen comments that say don't if you live in damp climates. More sound is good so may give it a go.
     
  18. Lint

    Lint Member

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    I've ridden in hard rain with the 05 and 99, both with the snorkel removed. Nothing happened
     
  19. 34468 Randy

    34468 Randy Secret Insider

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    Mine has been making that noise for over 200,000 km. Don't worry about it. That's what someone here told me a long time ago and I took their advice. Just ride is like a cheap two bit hooker.

    BTW. For those of you who don't live in Canada or USA, two bits = 25 cents or a quarter.
     
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