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Air Intake Flapper Removal and Tidy Up


Grum

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43 minutes ago, anth85 said:

means it would be shut for about 90% of my riding then

That's a bummer. It sounds great opened up. Most of mine is highway, so I get to roar! 

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I get the science behind the resonance of the intake air, but I am dubious of the amount of effect when it is bouncing backwards and forward through the air filter. In the cars I've had in the past they have had an intake, into an air filter box, the throttle body then into a resonator followed by the intake manifold. Mine is off and most likely staying off.

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On 6/21/2018 at 10:06 AM, anth85 said:

I get the science behind the resonance of the intake air, but I am dubious of the amount of effect when it is bouncing backwards and forward through the air filter. In the cars I've had in the past they have had an intake, into an air filter box, the throttle body then into a resonator followed by the intake manifold. Mine is off and most likely staying off.

 

I am absolutely convinced that the Flying Spaghetti Monster is real.

 

 

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  • 4 weeks later...

Well folks, the time has come for me to give this a try. I will follow the instructions and remove the yellow highlighted items in the first post. I will try and block the hose and air box opening in a reversible manner in case I want to return it to stock.

 

Any others who have recently done this on their 8th gen wish to chime in on their experience? Especially on what they you to block the hose after the "one-way valve" and the air box opening that remains? I am confused as the pic (from an OEM 2017 VFR00, if I read right) is solid and glued (!?) but someone mentioned they used window screen material which would be open (!?)

 

Not 100% certain about what I am doing but I'm due for the air filter change out so I figure it's as good a time as any... I'll report back my findings.

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So I removed the variable  air intake solenoid and block the hole with electrical tape. I have not removed the bypass control solenoid valve, the one way valve, the vacuum chamber nor any of the associated tubes/hoses. Can I block off the hose and run like this to feel the difference?

 

If not, how do I access all the other stuff to remove it? Is it as simple as removing the right side fairing, or is there other stuff to remove? Right now, I’ve got the tank up (seat and side panels removed) but did not take the fairings off...

 

Please let me know.

 

Thanks.

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4 hours ago, Ohlias said:

So I removed the variable  air intake solenoid and block the hole with electrical tape. I have not removed the bypass control solenoid valve, the one way valve, the vacuum chamber nor any of the associated tubes/hoses. Can I block off the hose and run like this to feel the difference?

 

If not, how do I access all the other stuff to remove it? Is it as simple as removing the right side fairing, or is there other stuff to remove? Right now, I’ve got the tank up (seat and side panels removed) but did not take the fairings off...

 

Please let me know.

 

Thanks.

 

Hi Ohlias.

To try your bike with the system disabled you only need to pull the vacuum hose from the diaphragm and block the hose. The intake flapper is open by default. Make sure any vacuum hose you have temporally pulled is blocked off. No need to remove fairings.

 

If you are happy with how your bike is running and wish to remove some under the tank clutter it's easy to remove the lot as per the diagram, you can always refit the system if you ever want to.

 

From memory I removed the four Intake Funnels below the air filter (take note to refit funnels to the same position) to allow the air filter housing to be raised a bit, this gives you access to remove the Vacuum Chamber and the Bypass Control Valve. Unplug the electrical connector of the Bypass Control Valve and wrap some tape or similar around the electrical connector to protect it from dirt. Remove all the vac hoses and hardware leaving the one vacuum line that comes from the throttle body to the One Way Valve, properly block off this vac hose and neatly tuck it away somewhere using a couple of ty-wraps. Re-fit your intake funnels, air filter and housing and your done.

 

WARNING - When lowering your Fuel Tank, make sure you gently take up the slack of the Tank Breather hose. On the right side of the bike you will see the hose and a coupling that joins the small hose to a bigger hose, gently pull at this point as you lower the tank. Not doing this can cause your breather hose to kink and block potentially causing dangerous vacuum to build up in your tank causing tank damage.

I've had the system fully removed for a few thousand k's now, the bike is performing beautifully in ALL respects IMO.

 

Cheers:beer:

 

Variable Air Intake.jpg

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1 hour ago, Ohlias said:

You're the best! Thanks for the quick and detailed response. Will be working on it tonight and riding tomorrow!

 

No worries, lets know how you go with the hardware removal.

Cheers

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Did this mod on my 08 800.

 

Also put O2 eliminators on. Initially just blocked the PAIR but then removed the hoses etc completely and block off the PAIR valves with Mello Dudes plates and all together they smoothed out the low revs beautifully.

 

Has anyone done the full monty mod on an 8th Gen yet? I'm still getting some low rev hesitation and wonder whether this engine respond to the mods as well as the old one did. 

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On 7/20/2018 at 8:21 AM, Grum said:

 

No worries, lets know how you go with the hardware removal.

Cheers

 

So I just blocked off the hole after removing the diaphragm and it sounds a little meaner in the mid range. However, it's raining and will be raining for a little while and I have no chance to really give it a try. Want to see how my fuel economy is too before removing all hardware. I do like the new sound though! ;)

 

I'll post back when I have some real news...

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I tore my bike apart yesterday to try this mod temporarily and compare the differences for my style of riding.  The bike was new-to-me with ~4K miles this spring, and as far as I could tell was 100% stock.  What I discovered was my flapper valve is NOT operational (open).  I found no evidence that a hose had been blocked, and everything seems to be in place.  I used the service manual procedure to test it (side stand up, gear indicator unplugged, etc.), and no bueno.  I also tested the bypass control valve, per SM, and it seems to function wnl. I then pulled the hose to the air intake diaphragm and used my thumb to feel for vacuum.  I didn't feel much (if any), rev'ed it, and felt no change. 

My concern is two-fold:

1) I really want to know how Honda INTENDED it to feel, sound, etc.

2) I'm bothered by what the lack of vacuum might be a symptom of.... is there a greater problem or is there something else not running efficiently?

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14 hours ago, headshrink said:

I tore my bike apart yesterday to try this mod temporarily and compare the differences for my style of riding.  The bike was new-to-me with ~4K miles this spring, and as far as I could tell was 100% stock.  What I discovered was my flapper valve is NOT operational (open).  I found no evidence that a hose had been blocked, and everything seems to be in place.  I used the service manual procedure to test it (side stand up, gear indicator unplugged, etc.), and no bueno.  I also tested the bypass control valve, per SM, and it seems to function wnl. I then pulled the hose to the air intake diaphragm and used my thumb to feel for vacuum.  I didn't feel much (if any), rev'ed it, and felt no change. 

My concern is two-fold:

1) I really want to know how Honda INTENDED it to feel, sound, etc.

2) I'm bothered by what the lack of vacuum might be a symptom of.... is there a greater problem or is there something else not running efficiently?

Hi Headshrink.

"You tore your bike apart " Bloody hell that sounds serious, you only had to raise the fuel tank! :smile: There will be no "differences for your style of riding" that I could possibly think of!

 

The testing of this system in the service manual is a bit vague. Even on the sixth gen I was not able to properly test the system as per the manual. Also the test for the diaphragm by applying vacuum is NOT correct it should CLOSE the valve NOT remain open as stated! Vacuum Closes the flapper valve.

  

Intake_Diaphramg.JPG

As for your concerns 1 and 2, there is plenty of info out there as to what this system was supposed to do, some good info, other just rubbish! The lack of vacuum you experienced was most likely caused by not achieving the operational criteria for the flapper to close.

As mentioned Honda have removed this system from the 2017 model, and IMO running a clean Air Filter will benefit you more than what this system could accomplish. 

My reason for removal was to simply clear some under tank clutter and after a few thousand kilometers without it the bike is running fine in all aspects. It was simple to removed and disable and fairly easy to reinstall if required.

Cheers.

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I also looked briefly at the 8G manual and wondered about that flapper test method, Grum. I know that if you unplug the flapper actuator, it stays open, and the vacuum is used to close it. 

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18 hours ago, Grum said:

Hi Headshrink.

"You tore your bike apart " Bloody hell that sounds serious, you only had to raise the fuel tank! :smile: There will be no "differences for your style of riding" that I could possibly think of!

 

The testing of this system in the service manual is a bit vague. Even on the sixth gen I was not able to properly test the system as per the manual. Also the test for the diaphragm by applying vacuum is NOT correct it should CLOSE the valve NOT remain open as stated! Vacuum Closes the flapper valve.

  

Intake_Diaphramg.JPG

As for your concerns 1 and 2, there is plenty of info out there as to what this system was supposed to do, some good info, other just rubbish! The lack of vacuum you experienced was most likely caused by not achieving the operational criteria for the flapper to close.

As mentioned Honda have removed this system from the 2017 model, and IMO running a clean Air Filter will benefit you more than what this system could accomplish. 

My reason for removal was to simply clear some under tank clutter and after a few thousand kilometers without it the bike is running fine in all aspects. It was simple to removed and disable and fairly easy to reinstall if required.

Cheers.

I think my brain must have flipped the typo, because I knew vacuum is supposed to close it.  My primary concern is why I'm not getting vacuum to start with.  I think I understand why people choose to do the mod, and the arguments others make against it, but why is mine not working?  In other-words, is my bike not running efficiently anyways due to some other undiagnosed problem.  My flapper never closes.  I couldn't test the diagram component independently without an adequate vacuum pump, but it seemed moot when I couldn't get vacuum in the line to it to begin with (under conditions that are supposed to close the valve).  I tested the solenoid and one-way valve per SM.

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6 hours ago, headshrink said:

I think my brain must have flipped the typo, because I knew vacuum is supposed to close it.  My primary concern is why I'm not getting vacuum to start with.  I think I understand why people choose to do the mod, and the arguments others make against it, but why is mine not working?  In other-words, is my bike not running efficiently anyways due to some other undiagnosed problem.  My flapper never closes.  I couldn't test the diagram component independently without an adequate vacuum pump, but it seemed moot when I couldn't get vacuum in the line to it to begin with (under conditions that are supposed to close the valve).  I tested the solenoid and one-way valve per SM.

Think you're worrying about nothing. Your only concern with this system effecting your bike adversely is a leak on any of the associated vacuum lines. You're really not going to notice anything wether it's working or not! Which is the reason for this thread and probably why Honda have removed it!

 

If you're keen to see it operate simply unplug the electrical connector to the control valve, then rig up a temporary 12v supply to the control valve to energise it, start your bike and the flapper should close.

Also from memory if you pull the vacuum hose from the control valve that leads to your diaphram, stick in your mouth, give it a good suck you will see the flapper move.

 

Again - unless you met all the operational criteria you will NOT see any vacuum at the diaphragm line to close the flapper, so I doubt your statement of it not working.

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  • 2 weeks later...
On 7/23/2018 at 8:50 PM, Grum said:

Think you're worrying about nothing. Your only concern with this system effecting your bike adversely is a leak on any of the associated vacuum lines. You're really not going to notice anything wether it's working or not! Which is the reason for this thread and probably why Honda have removed it!

 

If you're keen to see it operate simply unplug the electrical connector to the control valve, then rig up a temporary 12v supply to the control valve to energise it, start your bike and the flapper should close.

Also from memory if you pull the vacuum hose from the control valve that leads to your diaphram, stick in your mouth, give it a good suck you will see the flapper move.

 

Again - unless you met all the operational criteria you will NOT see any vacuum at the diaphragm line to close the flapper, so I doubt your statement of it not working.

I did try to meet all operational criteria (believe I did), per SM.  I'm not TOO worried, other than wanting to know WHY it isn't working.  I'll look again next time I'm on the lift.   If I knew the control valve was bad, not a big deal.... but I did bench test it, and it tested good.  I do want a relatively smooth power delivery down low, but also don't want to give up a noticeable amount of torque, because on this bike I'm there 98% of the time commuting.  I seemed to remember a bit more power way down low when I bought it, but that could also be me getting used to it.  I actually had to learn how to ride this one slow, but now I'm wondering what was so difficult.... so that part is super subjective, but does make me question if something happened during my ownership (purchased in March or April).  This bike is mechanically WAY more complicated than my last (CBR500r), which was more complicated than the one before (Ninja 250r), so there is always a learning curve for me to catch-up to and become comfortable with.  I just don't want to ignore something if it is wrong and pay the price down the road.... been there and done that.  So in conclusion, this isn't about should I or shouldn't I do the flapper mod, it's about understanding why mine isn't operational now.

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5 hours ago, headshrink said:

I did try to meet all operational criteria (believe I did), per SM.  I'm not TOO worried, other than wanting to know WHY it isn't working.  I'll look again next time I'm on the lift.   If I knew the control valve was bad, not a big deal.... but I did bench test it, and it tested good.  I do want a relatively smooth power delivery down low, but also don't want to give up a noticeable amount of torque, because on this bike I'm there 98% of the time commuting.  I seemed to remember a bit more power way down low when I bought it, but that could also be me getting used to it.  I actually had to learn how to ride this one slow, but now I'm wondering what was so difficult.... so that part is super subjective, but does make me question if something happened during my ownership (purchased in March or April).  This bike is mechanically WAY more complicated than my last (CBR500r), which was more complicated than the one before (Ninja 250r), so there is always a learning curve for me to catch-up to and become comfortable with.  I just don't want to ignore something if it is wrong and pay the price down the road.... been there and done that.  So in conclusion, this isn't about should I or shouldn't I do the flapper mod, it's about understanding why mine isn't operational now.

Hi Headshrink. 

Sorry but still think you're worrying about nothing. However, if I was desperately in need of knowing when this system operates, I would disconnect the electrical plug from the control valve, rig up a 12v lamp ( low wattage or LED and resistor) to the connector and temporarily mount the lamp where I could view it while riding. Whenever the lamp turns on is when the valve would energise which would apply vaccum to the diaphram to close the flapper. This test would ensure the ECU output was working, and by riding under various conditions you would soon learn when the flapper is activated. Just a thought, and a simple thing to try.

Cheers.

 

 

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On 8/7/2018 at 4:20 PM, Grum said:

Hi Headshrink. 

Sorry but still think you're worrying about nothing. However, if I was desperately in need of knowing when this system operates, I would disconnect the electrical plug from the control valve, rig up a 12v lamp ( low wattage or LED and resistor) to the connector and temporarily mount the lamp where I could view it while riding. Whenever the lamp turns on is when the valve would energise which would apply vaccum to the diaphram to close the flapper. This test would ensure the ECU output was working, and by riding under various conditions you would soon learn when the flapper is activated. Just a thought, and a simple thing to try.

Cheers.

 

 

That's a clever and inventive idea.  It may just add an extra 5-10hp 😉

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