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Discussion Starter #1
Hello everybody I'm running a mikuni carb on my Fatboy and when I put my hand by the carb area I can feel air is that normal for a mikuni or do I have a intake gasket problem? Bike runs great
 

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well if you had an intake problem, leak,, it wouldn't run great.. do you feel the air with the filter on, off or both?

Harley engines, especially at idle and low rpm,, with the air filter off,, it is normal to feel air flow going both ways.. suck and blow..

if you were a little clearer perhaps I, or others could give a better reply.,
 

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Well the thing is going to suck your pants leg if they loose enough. My bike had a cone and I never thought of it sucking my jeans until one day I rode home in the rain. The bike started cutting out because it was sucking water off my wet jeans. I found a different position for my foot.

Sent from my moto g(7) supra using Tapatalk
 

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Where exactly are you feeling air? Could it be open breather bolt holes in the heads?
 

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My guess would be the breather bolts are loose. Mine have come loose a few times. I can usually tell by the smell.
 

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loose breather bolts usually hav the symptom of excessive oil mist,,, making a good mess of the right side after 50 or so mile ride.
 

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Discussion Starter #10
My guess would be the breather bolts are loose. Mine have come loose a few times. I can usually tell by the smell.
Now the breather bolts your talking about are the air cleaner breather bolts ?I'm running a hyper charger style air cleaner not to sound to dumb but this is my first bike so I got a lot to learn
 

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Now that u mention it I have noticed oil on top of my primary not enough to drip like a leak just a little
I think Terry was talking about the right side,,, the primary is on the left side. So you might have a different issue on the left side. Or your breather bolts are leaking bad enough that the oil is leaking onto the head fins and running around to the primary side. Use a strong led light and look at the fins closely, you can see if they are wet and where it comes from and where the oil runs to.
 

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Discussion Starter #12
I think Terry was talking about the right side,,, the primary is on the left side. So you might have a different issue on the left side. Or your breather bolts are leaking bad enough that the oil is leaking onto the head fins and running around to the primary side. Use a strong led light and look at the fins closely, you can see if they are wet and where it comes from and where the oil runs to.
 

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Discussion Starter #13
Well fellas I tore into the fat boy thinking my air leak was coming from a bad intake gasket turns out I have compression releases on the heads behind the air cleaner thank u all for the helpful advice ? this being my first bike I'm still learning alot
 

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Well fellas I tore into the fat boy thinking my air leak was coming from a bad intake gasket turns out I have compression releases on the heads behind the air cleaner thank u all for the helpful advice ? this being my first bike I'm still learning alot
That's weird.
beyond weird.
 

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Discussion Starter #18
On each head it's got a small looks kinda like where a vacuum line would go both breather bolts have one I know the motors had a bunch of work done to it good size cam high compression valves etc
 

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Buy an aftermarket Evo top breather kit and funnel the kit to a hose that you run under the frame.
 

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Sounds like you might be missing some parts. If you have some air coming out the breather screws, you might be missing all the plumbing that would route it into the air cleaner on a stock bike. It probably went away when the hyper charger a/c was installed.

Most people just rig up some sort of road draft tube so it all comes out under the bike, hopefully not all over the rear tire. Or plumb it into a catch can. which would separate the oil from the fumes and need periodic maintenance.

If you had compression releases, they would more than likely be installed in the heads right beside the spark plugs, on the other side of the motor. They are manually operated, meaning you have to push the button on top of them to open, and compression will close them once the motor fires off.
 
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