| Author | Message | ||
     B1rdman |
I noticed these yellow air tubes connected to the main air intake...what are they there for? Are they stock? Why so intricate looking?   I also noticed on the air intake tube that there were HOLES, two of them, cut into it..why the hell would those be there? That pretty much bypasses the air filter which is not something I'm particularly happy about. Surely THIS isn't stock? Why would they be there?   Lastly, not pictured is the metal throttle body right behind this plastic air intake. On the bottom of the throttle body is an air port nipple...with nothing attached to it. Is that supposed to be like that or is there a hose or something that is supposed to be attached? I can take a pic if need be. | ||
| Alfau |
Breather system for upper cylinders, needs to be modified to keep the air filter free of oil. These things are primative.lol It's a love hate relationship. | ||
| Two_seasons |
Not as primitive as you may think. Your air box uses a technology called Helmholtz and here is a better explanation than I can give...http://en.wikipedia.org/wiki/Helmholtz_resonance Yes, you need a small nipple rubber cover for that opening at the bottom of the intake manifold. | ||
| Two_seasons |
FYI, once you put the outer cover of the airbox on with the air filter attached, the Helmholtz holes are free from contaminants that are in the outside air (dirt, bugs). It really is a clever design in engineering. It keeps the air pressure constant at the intake. Erik's bikes are engineered, not just another HD engine slapped in them! | ||
| Ratbuell |
To clarify - The yellow tubes are your crankcase breather hoses, that feed crankcase vapor into the intake. The tee is because one hose comes from the front head; one from the rear head; and they have to go into a single intake. The 'holes' are, as noted, helmholtz effect design. Loose explanation, it reduces intake noise ("honk") by cancelling air pulses that cause the noise. The first time I changed my very first M2 over from stock intake to a "race" intake, I thought the engine had started knocking - the intake pulses were so apparent through that open-element intake, it was almost startling. The nipple is a "ported" opening, it is not a constant bleed. It is there for California bikes that had a charcoal canister for emissions. The nipple caps deteriorate and fall off. It will not hurt anything to leave it open, or you can put on another cap...that will also deteriorate and fall off eventually...it's your call. (Message edited by ratbuell on April 14, 2013) | ||
| Natexlh1000 |
My X1 was a dealer's demo bike that they applied aftermarket parts. In doing that, they gutted the airbox so that unfiltered air was coming in from under the outer cover. Smart. I gave up trying to get them to give me the parts to revert it to stock and bought a forcewinder at around 8000 miles. Here is a trick for reassembling that thing: hold the air filter element from the opening behind the rear cover so that it is seated correctly as you tighten the outer cover. | ||
| B1rdman |
You guys rock. What if my air filter/tube still gets oil that is coughed up on occasion? Would the next step be the rocker cover upgrade and catch can? Regardless, good to know that everything is there on purpose lol. Never seen such a crazy setup. | ||
| Harleyelf |
XB rocker covers are the next step: if you're buying them new, get two fronts so the rear PCV valve won't hit your gas tank. If you get a set of used ones, consider swapping them; the front PCV valve will barely clear your frame if you mount a rear cover on it, but the rear cylinder gets lots more clearance from the gas tank if you mount a front cover on it. If you have to shave the front to clear the front motor mount, just take metal off the upper edge and stay away from the gasket sealing surface. Then mount a catch can or go back into the air cleaner box, depending on how much oil you are getting. If there is still a lot, change your rings. |
