You can see the loading of oil on the mesh in the pics below. However, the mesh material in both types can still gunk up with old oil. The umbrella is a slight loose fit when popped in there. It appears the mesh doesn't stop up the center as it has that hole in the middle and the umbrella should have a little clearance in the installed hole. Since 1979, HD Sportster breather valves have a drain back into the motor past the umbrella.Ģ004-up XLs also have a matt type strainer below the umbrella with a labyrinth past the umbrella with a drain hole there.īoth the Buell and 04-up Sportster umbrellas are in their own sealed containment so changing the umbrella if needed consists of replacing the whole unit. The Buell breather is similar to the 2004-up Sportster breather valve but without the oil drain-back.
The Buell type breather has been thought of by some as a much improved version of the Sportster breather system. PCV valves don't act as quick as the umbrella valve. This is not actually a PCV valve in the conventional sense.
The Buell breather valve (PCV as it is called in the parts book) is nothing more than a variation of the HD umbrella valve with a woven mesh insert and oil separator labyrinth under it. Then air/oil travels to the rocker boxes and separates via the breather valves on the rocker boxes.Ģ003 Buell XB-9R breather valve (17607-00Y), along with a grommet (17606-00Y), installs into the big hole in each rocker box cover.Ī vent hose connects each breather valve to the air cleaner backing plate. See also, Installing a Buell Rocker Box / Breather System on an Evo Sportster in the REF section of the Sportsterpedia.īuells use a reed in the gearcase to exhaust excess crankcase pressure to the gearcase. There is no dedicated section on the rocker box or umbrella valves (which seem to be regarded as mere gaskets).
#Harley evo camshaft cover breather tube install
It's only at the end of the Installation article does it say to install new gaskets on the middle rocker box (with the breather valve on the intake side). The FSM displays the same exploded diagram as the parts catalog in the front of the Cylinder Head section. It's assumed this was done to save money on printing the catalogs (replicated information deleted). This is the norm mostly throughout the subsequent catalogs with multiple (same) parts. It's the same for all of the parts on that page as well as each newer parts catalog (1 pushrod, tube ,lifter and related parts). Yet, the description shows that 2 umbrellas are required. The parts catalog only shows an exploded diagram of one rocker box assembly on the Rocker Arms, Covers and Pushrods page. The information is there but it's just not clear. The Parts Catalog and FSM are a bit confusing regarding how many umbrellas are used and where.
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