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Air Intake Flapper Removal and Tidy Up


Grum

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Hi All.

Some thoughts on this one.

As the Variable Air Intake system has been removed from the 8gen 2017 models, was looking at tidying up some plumbing and hardware by removing this system. See attached and a photo of the 2017 air filter cover.

 

Variable Air Intake.jpg

IMG_0325.JPG

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Sounds like a reasonable job. Are you intending trying it with hose blocked and solenoid disconnected first before removing the rest of the gubbins?

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9 hours ago, fink said:

Sounds like a reasonable job. Are you intending trying it with hose blocked and solenoid disconnected first before removing the rest of the gubbins?

Hi Fink.

Good point. I do intend on running the bike with the hose removed and blocked from the flapper diaphragm, by default the flapper is in the open position. If there's no noticeable change in performance l might go ahead and remove the stuff.

 

This may have come up before, but if anyone can tell me the benefit of all this hardware (which Honda have now removed), I'd like to know. Given that we are all riding around with air filters with varying degrees of flow rate, some OEM, some aftermarket, some very dirty others might be clean, surely this would have a greater impact, than simply altering the inflow air availability?

 

Cheers.

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Grum  tbh I have no idea.   I have a pipercross installed as opposed to theOE filter. 

 

I have only read as you no doubt have what others have achieved on other gens ( I hate those words)  and how they feel it has gone. As no doubt we both know only dyno ( cue rectal or gator) time will reveal any  benefits. 

I would happily give it a go but live in the Highlands  of Scotland hundreds of miles from civilisation, let alone a dyno?????. 

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9 hours ago, fink said:

 

I would happily give it a go but live in the Highlands  of Scotland hundreds of miles from civilisation, let alone a dyno?????. 

 

So where are you???

https://www.roughguides.com/article/remote-places-in-scotland/

 

Been to a few of the places mentioned, St. Kilda on my bucket list...

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Afaik it's Honda's attempt to make a variable geometry intake manifold, just without the variable geometry. There's a lot of surprisingly complex fluid Dynamics that goes on in an engine intake (exhaust too) due to the fact that the valves are not constantly open. What you get are a lot of high flow/low pressure and low flow/high pressure instances at the valves, which create pressure waves that resonate back out and around the air box chamber. If you tune the shape of the chamber just right, you can create positive pressure zones at just the right times to help fill (and negative zones evacuate, from the exhaust side) the cylinders. Of course, since the frequency of the valve openings changes with rpm, this effect only works at certain engine speeds--helping create the power band. A variable geometry intake could theoretically 're-tune' itself across multiple rpm ranges, thus widening the power band and making the engine more versatile. I believe Volvo was/is playing around with this in their cars, but Honda may have tried to do something similar with the vfr by changing not the geometry, but the amount (and thus, pressure) of intake air at certain rpm ranges.

 

All this to say I think it's there to strengthen your low and mid-range, but I don't know for certain.

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6 hours ago, Dutchy said:

 

So where are you???

https://www.roughguides.com/article/remote-places-in-scotland/

 

Been to a few of the places mentioned, St. Kilda on my bucket list...

 

live about 40 miles from the first one listed  in the rough guide article. The Mallaig Ambulance crew have to take the lifeboat over as its quicker than going by road.

 

I live on the Ardnamurchan peninsula. About 20 miles from HERE, also the Western most point of the British mainland

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After approx 400k's with the system disabled and the flapper in the fully open position, I can honestly say the bike is as Good if not Better than with the system operational SUBJECTIVELY speaking.

Tried a number of riding variables from idle to red line, the bike performs as good as ever. SO, if its good enough for Honda to remove this system from the 2017 model, I'm going to remove all this hardware clutter ASAP.

Cheers.

Post Edit - Yesterday 14/Dec/17. Removed all hardware as per top drawing and plugged main vac hose, bike running fine.

 

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  • 4 weeks later...
On 09/12/2017 at 5:38 AM, Grum said:

Hi All.

Some thoughts on this one.

As the Variable Air Intake system has been removed from the 8gen 2017 models, was looking at tidying up some plumbing and hardware by removing this system. See attached and a photo of the 2017 air filter cover.

 

Variable Air Intake.jpg

IMG_0325.JPG

Hi, i didn't think found my photo on this forum. Ahaha

 

I didn't change my stock air filter but it think they removed the system like you did and plug the hole on the throttle body.

 

When the time comes, i will take some photos of that.

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1 hour ago, Kwee69 said:

Hi, i didn't think found my photo on this forum. Ahaha

 

I didn't change my stock air filter but it think they removed the system like you did and plug the hole on the throttle body.

 

When the time comes, i will take some photos of that.

 

 Bonjour mon ami. Yes thank you for your picture, it was just the inspiration I needed to get rid of the system.

Au revoir. 

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  • 4 months later...
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On 12/8/2017 at 11:38 PM, Grum said:

Hi All.

Some thoughts on this one.

As the Variable Air Intake system has been removed from the 8gen 2017 models, was looking at tidying up some plumbing and hardware by removing this system. See attached and a photo of the 2017 air filter cover.

IMG_0325.JPG

I saw your link from the other post to this one and I was wondering how they changed the intake with removal of the flapper. Thought it might make for a nice retrofit to earlier model 800s.

I couldn't believe that was factory until I just searched ebay and saw one there. That is awful! Looks like an ok DIY job, but not OE...

In any case, we've been removing the flapper and snorkel since 1998, so go for it!

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On 29 May 2018 at 1:32 AM, KevCarver said:

I saw your link from the other post to this one and I was wondering how they changed the intake with removal of the flapper. Thought it might make for a nice retrofit to earlier model 800s.

I couldn't believe that was factory until I just searched ebay and saw one there. That is awful! Looks like an ok DIY job, but not OE...

In any case, we've been removing the flapper and snorkel since 1998, so go for it!

 

Hi Kev

Totally agree sure does look a bit DIY for a Honda update, however reckon Honda would have squillions of air box lids floating around as the 6 and 8 gens are the same. A simple glue in bung is the cheap but effective option I guess.

Have done around 6,000k's since removing this system - bike is as good as gold!

Cheers.

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5th is the same also! Some slight differences in interior shapes, and 5th has provisions for mounting the coils, but same filter fits all 800s.

Curious on the '17+ flapper delete; is the actual flapper glued down or removed? 

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Let me get this straight, 2014,15 &16 bikes have all that extra hardware doing something no one knows and in 2017 (last year of production for current gen VFR800s, they (Honda) plugged it up as in the pic above?

 

Does the intake sound better? How is fuel economy on long trips? Any more dirt in the filter? How much did the stuff removed weight? I love a good weight reduction! 😉

 

Thanks for the info!

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On 5/29/2018 at 1:57 PM, Ohlias said:

Let me get this straight, 2014,15 &16 bikes have all that extra hardware doing something no one knows and in 2017 (last year of production for current gen VFR800s, they (Honda) plugged it up as in the pic above?

 

Does the intake sound better? How is fuel economy on long trips? Any more dirt in the filter? How much did the stuff removed weight? I love a good weight reduction! 😉

 

Thanks for the info!

It's been on all 800s from 1998!

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  • 3 weeks later...
On 5/29/2018 at 7:57 PM, Ohlias said:

Let me get this straight, 2014,15 &16 bikes have all that extra hardware doing something no one knows and in 2017 (last year of production for current gen VFR800s, they (Honda) plugged it up as in the pic above?

 

Does the intake sound better? How is fuel economy on long trips? Any more dirt in the filter? How much did the stuff removed weight? I love a good weight reduction! 😉

 

Thanks for the info!

Fuel economy is top on VFR 800 2017(Euro 4) 

 

I don't know about the weight. I think about 800 grams to 1 kg.

 

The intake sound is very good because before(on 2014, 2015, 2016) the flapper open at 6500 rpm. 

20180616_205541.jpg

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I yanked mine off, snorkel as well. Glued some window screen material over the holes. I'm sure it's not optimized perfectly, and I think it may have even lost some low end, but it sounds 1000x meaner. My bike, I like it. 

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removed mine last night, first thoughts on it on my ride in this morning was slightly more responsive on the low end. Though not enough to conclusively say its not placebo effect.

 

At what revs would a flapper open out of curiosity?

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The science is real. Keeping the snorkel will keep the designed resonance. Maybe I'll measure mine this weekend and plug in the math. It's been sitting in my bucket of weight savings, along with the carbon can and exhaust. 

 

Nonetheless, I don't need the 5hp, but I greatly enjoy the noise. Leaving it in the bucket. 

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