04-01-2017, 10:35 PM
On page 1-31 of the 2013 service manual is a brief description and diagram of the crankcase emission control system. Blow-by gas is returned to the front air cleaner housing and thus is "recycled" into the throttle body. It's a closed system to prevent discharging crankcase emissions into the atmosphere.
Over time, fluids accumulate in the front and rear air cleaner housings. The picture in post one of this thread is the drain tube for the front air cleaner housing. The capped drain tube under the bike is for the rear air cleaner housing, See page 3-6 of the 2013 service manual. The manual calls them crankcase breather tubes but they are simply drain tubes for fluids that accumulate in the front and rear air cleaner housings. They need to be capped to prevent air intake that bypasses the air filter.
Let me know if any of this is inaccurate as it's my interpretation of information in the service manual.
Over time, fluids accumulate in the front and rear air cleaner housings. The picture in post one of this thread is the drain tube for the front air cleaner housing. The capped drain tube under the bike is for the rear air cleaner housing, See page 3-6 of the 2013 service manual. The manual calls them crankcase breather tubes but they are simply drain tubes for fluids that accumulate in the front and rear air cleaner housings. They need to be capped to prevent air intake that bypasses the air filter.
Let me know if any of this is inaccurate as it's my interpretation of information in the service manual.