US/AC II 8th gen fuel system mods help please

Discussion in 'Mechanics Garage' started by Samuel, Aug 1, 2017.

  1. Samuel

    Samuel Member

    Country:
    United States
    Joined:
    Aug 15, 2006
    Messages:
    798
    Likes Received:
    307
    Trophy Points:
    63
    Location:
    Los Angeles County
    Map
    Hi All,

    I’m in the middle of some mods and am asking for a little help/guidance/advice/feedback please.

    2015 VFR800 deluxe/US model (AC II, I believe)

    I’ve been referencing/using my hard copy of the Honda service manual but here is a copy for anyone who may be able to help but doesn’t have a copy.

    http://www.vfrdiscussion.com/index.php?/files/file/251-2015vfr800zip/
    (Big Thanks to Amoreira88 !!)

    I just finished removing the Pair Control Solenoid Valve (7-22 in the manual) and the front and rear Pair Check Valve covers and hoses. (I replaced the covers with block off plates from Smart Moto http://www.ebay.com/itm/PAIR-Valve-Eliminator-SMOG-block-off-plates-Honda-CBR-VFR-800-600-1100-1000-PCV-/252055880649?vxp=mtr&hash=item3aafb383c9 . I left all the baffle plates in and reused the OEM Pair Check Valves after removing the reed assemblies (maybe it’s me but I think the phillips head screws are break away – I had to use vice grips to remove them and all 4 broke off)). Disconnected the 2P connector (leaving the MAP connector in place) and taped it closed.

    I also removed the Intake Duct Valve Diaphragm (7-24) and snorkel from the Air Cleaner Housing as well as the EVAP Canister (7-28). I rerouted the hose from the fuel tank to the EVAP canister down to the left side next to a couple of other hoses but do I still need that hose attached to the fuel tank since the canister is gone?

    What I’m thinking about next is removing the Intake Duct Control Solenoid Valve (7-25/26), one way valve, vacuum chamber and hoses. Does anyone know if that would be a good/bad idea? I was hoping to just remove all that and tape off the 2P connector… ??

    I was also hoping to remove the EVAP Purge Control Solenoid Valve (7-27) and hoses and tape off the 2P connector. Any problems with that? If that’s feasible, I wasn’t sure what to do with the EVAP purge control solenoid valve-to-throttle body hose [2] (7-27) – since it seems to go through the valve and then down to the canister (which is no longer there), I was thinking to just leave it hanging down out of the way?

    While I’ve got everything apart/exposed, any other thoughts or recommendations on things to do to my bike before I put everything back together?

    Thanks in advance for any help!
     
  2. Terry Smith

    Terry Smith Member

    Country:
    New Zealand
    Joined:
    Nov 18, 2013
    Messages:
    2,070
    Likes Received:
    307
    Trophy Points:
    98
    Location:
    Auckland, New Zealand
    Map
    First up let me say I have a 5G, and I'm not a strong believer in the benefits of the snorkel/flapper elimination. The rest of the stuff (evap canister and PAIR) are emissions related stuff that won't change how the bike runs but will feel good to put in the skip. I certainly de-PAIRed mine as soon as I got it, and have played with deactivating the flapper, but prefer it functional.

    The key thing in all these mods is to ensure that you don't get any vacuum leaks back to the airbox, and you don't upset the ECU by removing something that it expects to be present. For that reason you might need to check whether the solenoid for the flapper or evap system needs to be connected. On my 5G, the PAIR solenoid does not, and I have the connector taped up and tucked away.

    As you will have done with the PAIR air connection, if you remove the solenoids, you should ensure the hose connections to the evap and flapper solenoids are sealed off either at the hose end or at the airbox, so you don't have a vacuum leak.

    You should leave the hose connected to the fuel tank as this is the air vent. Not sure it will matter where it goes, ideally to wherever the EVAP vent went to, probably low on the left side of the bike under the motor..
     
    Samuel likes this.
  3. Samuel

    Samuel Member

    Country:
    United States
    Joined:
    Aug 15, 2006
    Messages:
    798
    Likes Received:
    307
    Trophy Points:
    63
    Location:
    Los Angeles County
    Map
    Thanks Terry.

    Well, I took the plunge today. Removed the air cleaner to access the intake duct control solenoid valve and removed it all. Taped off the 2P connector and blocked off the one remaining hose going to the throttle body. Reinstalled the air cleaner and also swapped out the OEM air filter for a piper cross - like a few others have mentioned, it's easier to put the filter into the upper lid first and then massage it onto the lower half (the contour/outline of the piper cross I got, from an authorized dealer, did not exactly match the air cleaner and a little working the edges in was required - nothing too difficult). Then I removed the EVAP purge control solenoid valve assembly. Taped off the 2P connector and blocked off the hose going to the throttle body. Reconnected the tank and primed the fuel pump a few times. Bike started ok, idled ok, and no engine light came on so that was good. There was a significant increase in noise (growl) from under the fuel tank (I had also removed the intake duct diaphragm and taped the flapper valve down, open position). I'm not sure if it was me, but throttle response seemed a tad soft or slow and there was some popping from the exhaust upon sudden throttle chop from higher (over 7000) revs. I didn't get to take it out on the road because I have some more mods in store and I didn't have time to button everything up and put the fairings back on. (oh and I did leave the evap hose connected to the fuel tank)

    If it's not my imagination and the system has changed enough to cause a difference in running condition, my next question is how long does it take for the ECU to adjust for the new set up? (yes, I re-connected the MAP sensor and hose and the connector under the middle of the bottom half of the air cleaner)
     
  4. Terry Smith

    Terry Smith Member

    Country:
    New Zealand
    Joined:
    Nov 18, 2013
    Messages:
    2,070
    Likes Received:
    307
    Trophy Points:
    98
    Location:
    Auckland, New Zealand
    Map
    I might be wrong, but I don't believe the FI system will adjust to any changes in intake or exhaust flow; if you want to change things, you are going to need a Power Commander or similar.
     
  5. Samuel

    Samuel Member

    Country:
    United States
    Joined:
    Aug 15, 2006
    Messages:
    798
    Likes Received:
    307
    Trophy Points:
    63
    Location:
    Los Angeles County
    Map
    Copy that Terry, thanks. I was hoping that if the O2 sensors were picking up a leaner than normal condition (e.g. possibly from replacing the OEM air filter with the piper cross) that the bike would adjust and richen slightly...
     
  6. ksoholm

    ksoholm New Member

    Country:
    United States
    Joined:
    Jan 23, 2017
    Messages:
    244
    Likes Received:
    32
    Trophy Points:
    28
    What compelled you to mess with your very carefully engineered bike? Is there a well-documented, problematic running condition on the 8th Gen that is cured by what you did? Did you find any before-and-after dyno evidence that Pipercross filters flow significantly better than OE, and that it, and PAIR/snorkel/flapper removal, cause increases in the area under the curve? Why do you suppose Honda installed a flapper/snorkel?

    Yours is a text-book case of fixing something until it breaks; the advice is to put it back together to stock. That would cure everything.
     
  7. NorcalBoy

    NorcalBoy Member

    Joined:
    Aug 29, 2007
    Messages:
    5,421
    Likes Received:
    546
    Trophy Points:
    113
    Location:
    Desert Southwest
    Map
    Because they had to do it.....regulations. Doesn't mean it can't be successfully removed, however, I do agree that there are some people that shouldn't fuck with stuff without adult supervision.
     
    Rsparky likes this.
  8. ksoholm

    ksoholm New Member

    Country:
    United States
    Joined:
    Jan 23, 2017
    Messages:
    244
    Likes Received:
    32
    Trophy Points:
    28
    But, wait! Airbox snorkels are integral parts of the entire engine tuning, and are very carefully designed to maximize peak torque right where engines need it most. Snorkels and airboxes are tuned resonance chambers; messing withe them will likely hurt power and torque curves.

    PAIR? Yep, regulations--cleaner running during warm-up.
     
  9. Samuel

    Samuel Member

    Country:
    United States
    Joined:
    Aug 15, 2006
    Messages:
    798
    Likes Received:
    307
    Trophy Points:
    63
    Location:
    Los Angeles County
    Map
    Your opinion noted. Suum Cuique.

    FWIW, since as far back as I can remember, I've always tinkered with stuff, taken stuff apart, put stuff back together (usually successfully haha), etc. "well-documented" is subjective but I've read "quite a bit" that PAIR/flapper removal/modification has helped improve the performance of "quite a few" bikes. I don't have convenient access to a dyno and I have other things I would like to spend my money on. I don't have any empirical evidence that PC filters flow better than OEM but that's what I'm guessing. As far as improving performance with the mods, I read enough here on VFRW and over at VFRD and a "bunch" of other websites that I was willing to take the chance. I don't KNOW (100% for sure) why Honda installed a flapper system but I've read people opine that it was to meet noise requirements. As far as "very carefully engineered", well, I definitely couldn't design anything better than anything on the market right now - that being said, I'm not really concerned about engineering/designing/building that is (apparently) strictly for noise and/or emissions regulations. I don't KNOW but I'd be surprised if any competition motorcycles have the stuff I ended up removing.

    I took it out for a very brief run yesterday - brief as in 10-15 miles and No high speed/WOT runs. The bike actually felt pretty good. Midrange throttle response seems a little bit livelier - to get the bike to move down the road seems to take a little less twist of the wrist (guessing a range from 3000-6500 rpm) and it seems like it doesn't bog as easy (e.g. if I'm slightly cracking the throttle open while moving slowly in a higher gear) as it used to. But, it could be all in my head too. Either way, so far, it was worth my time and I'm guessing future oil changes should be a little easier as well with the EVAP canister removed.
     
    Last edited: Aug 9, 2017
  10. Samuel

    Samuel Member

    Country:
    United States
    Joined:
    Aug 15, 2006
    Messages:
    798
    Likes Received:
    307
    Trophy Points:
    63
    Location:
    Los Angeles County
    Map
    And not every adult is capable of proper supervision either... ;)
     
  11. Rsparky

    Rsparky New Member

    Country:
    United States
    Joined:
    Apr 21, 2016
    Messages:
    109
    Likes Received:
    17
    Trophy Points:
    18
    You know what else was very carefully engineered? The wiring harness, main fuse, regulator/rectifier and stator. Which all are known to fail.

    I AM an engineer. We screw up sometimes. And other times we overbuild things with huge safety factors. Maybe because it fits the regulations with less of a headache on our end to try to skirt the line. Maybe it costs less. Maybe we just want to watch end users play with it. Honda knows any REAL biker is going to tinker.

    I did. It's fun. Don't be a tool.
     
    Samuel likes this.
Related Topics

Share This Page