X1 Half Dollar Sized Holes in the Intake Snorkel

[Smuve]

Does anyone know the purpose of the two-half dollar sized holes in the intake snorkel? It seems like a chance for unfiltered air given the design of the air box sealing.

[Blks1l]

That whole area inside the airbox is filtered air unless yours has been modified somewhat. that is also considering that the airbox lid seal and air filter seal are in good condition.

[Zac4mac]

You say two holes are inside the filter, right.
Just guessing, since there are two, I’d think for front and rear breather hoses.

Z

[Aesquire]

Holes in the sides of the snorkel?

Noise tuning holes. Change the frequency of intake noise. Like a flute.

By Law, a new, factory, motorcycle is allowed X decibels of noise, measured in a very specific way with very specific equipment. Pages of specs. Distances, frequencies, etc.

Harley has that equipment. They use it to quiet noise they don't want so they can "spend" it on a pleasing exhaust note... Seriously. There's extra ribs on the hidden side of aluminum castings ( like the cam/ignition cover ) to tune down the high pitched rattles. Lots of time & money go into that.

Intake noise, the whistling, the sound of valve train through the carb/throttle body, is less pleasing than exhaust thud thud...thud thud, per customer surveys and common sense. ( I personally like the sucking sound, but it's right by my knee ( on my race only intake ) goes right up my helmet neck hole, and does interfere with headset music enjoyment )

Thus the musical tuning of the intake boxes on your X1 & different tuning in my M2. Different volumes, shapes, tone and musical characteristics.

[Aesquire]

Btw, I modified my breather system to a catch can, so the dirty oil & water vapor condenses safely, and doesn't run down the engine from the air cleaner. ( And onto legs in the leg forward H-D bikes ) The performance advantages are not measurable, a Watt? But the convenience and longer time between cleaning the filter is worth it.

I have tried aftermarket catch cans. They make fancy billet ones. I don't like not being able to tell if there's a change in volume of output. ( worn rings, for example ) Plus I'm sarcastic, so I use a 16oz plastic pop bottle and change it when it gets grungy. 5¢ & if you rinse it out, they give that back. I also change brands each time, just to see if anyone notices. On a good running engine it's just table spoon amounts on a long ride and the water evaporates with my setup & keeps the bike cleaner.

Pop bottle size is big enough to hold months of riding spew. I run the 2 hoses halfway down the bottle so there's vertical space for vapor to settle & the hoses won't suck up liquid from the bottom. Drain before that if your bike makes more than mine. Tie wrapped to the frame mostly behind the side cover.

I did spend a few bucks on a banjo bolt & other hardware to clean up the breather system and keep the air filter & box much cleaner. I think it was worth it. Ymmv.

[Smuve]

Thanks for your responses. I have to agree with Aesquire, that the holes are for intake noise tuning. Not sure about other models, but the X1 has what the parts catalogue and manual calls an intake snorkel. It is this snorkel that has the holes.

[Aesquire]

The boxes are different on the M2 & X1, but that's almost all exterior shape. I modified my stock airbox, eliminated the snorkel and little box the filter lived in, with a home made strap to hold the filter, and substituted a velocity stack for the snorkel. Flow is much improved, noise up only a little. The intake opening is only about the size of the palm of your hand, but you do need to richen the jetting up. I use the same jetting for the completely open sided Race filter, the Carbon Fiber Ham Can cover. Which DOES let me hear the valves through the intake.