The other day, while I had the bike all tore apart, I decided to look at what they're doing for breathers on this bike. The one up front with the vacuum line and the little squirrel cage corn-fuses me a little. I won't touch that thing. The rear one has me wondering. It's got this big 3/4" hose feeding into the airbox. So i stuck a little screw driver into the hole in the air box to feel what's in there and the hole gets really small.

Let's say I finger out how to get some sort of cutting tool in there, would it hurt anything to open that hole up some? I can't see how restricting the breather, like they have it is a good thing.

 

On my bike I plugged the hole going into the airbox with silicone and installed one of those breather filters from Auto zone on the hose. That's the breather under the carb. The front tube that went from the crankcase to the emission pump, I made a hose and used another breather filter when I disconnected the smog stuff. Seems like it works ok so far.

 

I don't understand why folks put filters on the breather hose. This isn't a car with a PCV system putting a suction on the engine. The breather should vent blowby out and not suck air in. My Honda XRs had the breathers just open ended from the factory and always blew out. Why not just shove the open end of the new breather into the snorkel and skip the extra filter?