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Pulled Off Air Filter - Is This Normal?


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Hi Everyone,

 

I bought a 2010 VFR1200F (38,000 miles) from a dealer last week, and after a few rides I'm taking it apart to see what kind of shape it's in. I pulled off the surprisingly clean stock air filter to see there's a multitude of oil gunk and some other things in the air box, not totally unexpected, but I noticed my throttle valves are variously dirty, particularly the front left one, which is black with dirt compared to the other three. Has anyone else seen this in their air box when they've opened it up? I'm trying to figure out if this normal or if my air filter wasn't sealed and it just happened to be by that intake trumpet. The air filter seems recently changed, but it could have had a K&N in it for most of it's life for all I know. Also there was a big-ish piece of acorn or a beetle shell in the air box too. Is it possible that came in from the breather tube or somewhere else? Interested to hear your thoughts.

PXL_20210713_003616815.jpg

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That one intake butterfly seems very odd.  How does its spark plug look compared to the other 3?   Even if a localized air filter leak it would seem that it would affect the other 3, though to a lesser extent.  Can you start it with the filter out and note whether that one butterfly is moving equally with the other 3 as throttle is applied? 

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Not too familiar with the 1200 but could that intake be nearest the Crankcase Ventilation inlet, perhaps this intake sucks in most of the crankcase fumes. Maybe a case of overfilled engine oil at some stage?

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The front centre is the engine crankcase breather. And if bike is normally stored on its side stand then any oil residue will run to the  front left plastic intake trumpet & seep down between the plastic & metal throttle body. When engine runs the vacuum pressure will suck it on to the butterfly & into the intake. 
 

My 5th gen does the same on #3 pot, as the breather is in the rear right corner of the airbox. Don't worry about it. 

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Honda's term for them in "resonator".   Maybe they change the tone or loudness of sound emanating from the airbox, or they could have some effect on changing the airflow through it .  Goes to show that Honda puts a lot of thought in to those - they're not just there to hold the filter. 

 

Great observation by Mohawk about the bike being on the side stand and breather effluent flowing to the downhill side and ending up in that intake tube.  Once pointed out it seems to make so much sense out of something that otherwise made no sense! 

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5 hours ago, Cogswell said:

Honda's term for them in "resonator".   Maybe they change the tone or loudness of sound emanating from the airbox, or they could have some effect on changing the airflow through it .  Goes to show that Honda puts a lot of thought in to those - they're not just there to hold the filter. 

 

Great observation by Mohawk about the bike being on the side stand and breather effluent flowing to the downhill side and ending up in that intake tube.  Once pointed out it seems to make so much sense out of something that otherwise made no sense! 

 

Yeah I agree, that seems to make the most sense. This bike was definitely on it's side stand a lot seeing as how it doesn't have a center stand. As for the little piece of acorn, I thought about it more and I suspect that must have fallen in during the last filter change. Either way, this explanation puts my mind at ease.

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  • 2 weeks later...
On 7/13/2021 at 11:50 AM, DFOTECH said:

What are those 2 white plastic containers in the breather on either side?  My G5 doesnt have those

Kambucha fermenting reactors. Honda was originally hoping for big sales on Kalifornia market....

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I take it that those white plastic bottles in the airbox are NOT connected to anything, right ? 
 

If so they are sound resonance chambers, probably there just yo reduce intake noise for passing tests. Take them out & see if it affects the sound. 

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1 hour ago, Mohawk said:

I take it that those white plastic bottles in the airbox are NOT connected to anything, right ? 
 

If so they are sound resonance chambers, probably there just yo reduce intake noise for passing tests. Take them out & see if it affects the sound. 

Don’t listen to that advice. You know how hard it is to get back into air filter box 😂 

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