[[:techtalk:menu|{{ :techtalk:gototechnicalmenu.jpg|}}]] ====== REF: Engine Mechanicals - Sub-04J ====== \\ ====== Further Study of Evo Sportster Breather Valves ====== See also in the REF section of the Sportsterpedia: \\ * [[techtalk:ref:engmech04k|Breather Valves (1957-Up)]] (list of breather valve changes) * [[techtalk:ref:engmech05|Breather Venting / Relocation]] * [[techtalk:evo:engmech07|Evo Crankcase Ventilation (1986-Up)]] \\ \\ ====== Comparing L1984 and 1991 Umbrella Valves ====== L1984-1990 umbrella valve (26856-82). \\ 1991-2003 umbrella valve (26856-89). \\ **Dims**: ((Gary E of the XLFORUM https://www.xlforum.net/forum/sportster-motorcycle-forum/sportster-motorcycle-motor-engine/sportster-motorcycle-bottom-end/195092-rigid-evo-oil-check-ball-spring/page8?t=2071387&page=8)) \\ Outside diameter: \\ L1984 - 1.25" \\ 1991 - 1.0" \\ Edge thickness (1/8" in average): \\ L1984 - 0.036" \\ 1991 - 0.041" \\ * The pic below shows the left side (filter side) that faces into the cam box. * It's center inside diameter is slightly larger than the 1.25" OD (-82) umbrella valve. * The two 'C' shaped slots that do the breathing have an OD of 1". * As a result, the 91-03 umbrella valve with its diameter of 1" may not perform correctly in L84-90 models since there is likely to be leakage. |{{:techtalk:evo:oil:umbrella_valve_by_gary_e.jpg?direct&300|}}|{{:techtalk:evo:oil:breather_baffle_tube_by_gary_e.jpg?direct&300|}}| | Umbrella (check) Valves \\ L - (26856-82), R - (26856-89) ((photo by Gary E of the XLFORUM https://www.xlforum.net/forum/sportster-motorcycle-forum/sportster-motorcycle-motor-engine/sportster-motorcycle-bottom-end/195092-rigid-evo-oil-check-ball-spring/page8?t=2071387&page=8)) | Breather Baffle Tube (26917-84) ((photo by Gary E of the XLFORUM https://www.xlforum.net/forum/sportster-motorcycle-forum/sportster-motorcycle-motor-engine/sportster-motorcycle-bottom-end/195092-rigid-evo-oil-check-ball-spring/page8?t=2071387&page=8)) | \\ [[:techtalk:menu|{{:techtalk:gototechnicalmenu.jpg|}}]]