Differences

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--- techtalk:ih:oil03u [2025/06/29 16:30] – [1970-1971 XR-750] hippysmack
+++ techtalk:ih:oil03u [2025/10/21 03:14] (current) – [1988-up XR-750 Oil Pump] hippysmack
@@ Line 2: / Line 2: @@
 ====== IH: Oiling & Lubrication - Sub-03U ======
 ====== XR-750 Oil Pump - Parts Lists and Information ======
 -1987 racing pumps ran 1/4 speed of engine RPM.\\
 The 1/4 speed gears on the both the breather shaft and pinion shaft were cut at a taller angle than on street motors.\\
 Below is a pic showing the difference in teeth angles.
-{{:techtalk:ih:oil:half_speed_vs_quarter_speed_oil_pump_drve_gears_by_thefrenchowl.jpg?direct&600|half_speed_vs_quarter_speed_oil_pump_drve_gears_by_thefrenchowl.jpg}}((pic by The French Owl of the XLFORUM https://www.xlforum.net/forum/sportster-motorcycle-forum/sportster-motorcycle-era-specific-and-model-specific/ironhead-sportster-motorcycle-talk-1957-1985/203311-nos-cases#post4542140))
+{{:techtalk:ih:oil:half_speed_vs_quarter_speed_oil_pump_drve_gears_by_thefrenchowl.jpg?direct&600|half_speed_vs_quarter_speed_oil_pump_drve_gears_by_thefrenchowl.jpg}} ((pic by The French Owl of the XLFORUM https://www.xlforum.net/forum/sportster-motorcycle-forum/sportster-motorcycle-era-specific-and-model-specific/ironhead-sportster-motorcycle-talk-1957-1985/203311-nos-cases#post4542140))
 ====== 1970 XR-750 Oil Pump ======
@@ Line 60: / Line 58: @@
     * Breather Timing (improved): Valve opens at (5° ATDC) front cylinder. Valve closes at (105° ABDC) front cylinder. \\ Slot in upper cover must be widened to app .340" to make this possible.
   * The motor is no longer fed only a portion of the pump's full capacity of oil as the bypass system of previous year pumps has been deleted. \\ Coincidently, the return gears are bigger to allow more oil to be scavenged from the motor.
 There is a desceprency between the 1972 and 1975 parts books in where the upper and pump mounting gaskets are switched between the 2 catalogs. \\
@@ Line 75: / Line 72: @@
 ====== 1975-1987 XR-750 Oil Pump ======
   * Pump speed is 1/4 of the engine speed.
   * Return gears operate at a 2:1 ratio of the feed gears.
@@ Line 106: / Line 102: @@
 {{:techtalk:ih:engmech:1975-1987_xr-750_breather_gear_26331-74r_pic2.jpg?direct&300|1975-1987_xr-750_breather_gear_26331-74r_pic2.jpg}} ((pic used with permission)) {{:techtalk:ih:oil:1975-1987_xr-750_oil_pump_26203-74r_pic1_by_mofosheee.jpg?direct&300|}} ((photo by Mofoshee of the XLFORUM https://www.xlforum.net/forum/sportster-motorcycle-forum/sportster-motorcycle-era-specific-and-model-specific/ironhead-sportster-motorcycle-talk-1957-1985/4964069-1975-sportster-factory-shop-manual-basket-case-rebuild/page2)) {{:techtalk:ih:oil:1975-1987_xr-750_oil_pump_26203-74r_pic2_by_mofosheee.jpg?direct&300|}} ((photo by Mofoshee of the XLFORUM https://www.xlforum.net/forum/sportster-motorcycle-forum/sportster-motorcycle-era-specific-and-model-specific/ironhead-sportster-motorcycle-talk-1957-1985/4964069-1975-sportster-factory-shop-manual-basket-case-rebuild/page2)) \\
 ====== 1988-up XR-750 Oil Pump ======
+The original 1988 oil pump body was made out of magnesium and later it was made out of aluminum but the part number for the body stayed the same. The part number for the pump assembly did change from 26203-88R to 26203-88RA at least by 2002. However, the only part number that changed between the two assemblies was the 1/4" return outlet fitting from 62570-83 to 25259-93A. \\
   * Pump speed is 1/2 of engine speed.
   * Return to feed ratio is 4:1.
@@ Line 124: / Line 121: @@
 |45830-48|62570-83|25259-93A|63541-74R|26227-58|11159|:::||||
-Pump Body 26217-88R \\
+Below is the magnesium pump body (26217-88R) and parts including the covers and gears. ((pics by Flattracker94 of the XLFORUM https://www.xlforum.net/forum/sportster-motorcycle-forum/sportster-motorcycle-era-specific-and-model-specific/xr-sportster-motorcycle-talk-xr750-xr1000-xr1200/xr-750/187566-xr750-engine-from-rag-to-ripper/page4)) \\
-This is just the body without upper and lower covers. ((photos courtesy of ROBERT EVANS)) \\
+The left side of this pump has 5/8" dia. fitting for scavenging the sump and the 3/8" dia. for oil supply from the tank. The right side of the pump has ball/spring check valve and 3/8" dia. oil return line to tank. The front side of the pump body has NPT plugs to block off passages from manufacturing/machining oil galleys. Can't make this pump any smaller and no reason to make it bigger, adding weight. Also the pump sits very close to the right side lower frame tube with very little clearance. \\
-{{:techtalk:ih:oil:xr-750_oil_pump_body_26217-88r_pic1_by_robert_evans.jpg?direct&300|}} {{:techtalk:ih:oil:xr-750_oil_pump_body_26217-88r_pic2_by_robert_evans.jpg?direct&300|}} {{:techtalk:ih:oil:xr-750_oil_pump_body_26217-88r_pic3_by_robert_evans.jpg?direct&300|}} \\
-{{:techtalk:ih:oil:xr-750_oil_pump_body_26217-88r_pic4_by_robert_evans.jpg?direct&300|}} {{:techtalk:ih:oil:xr-750_oil_pump_body_26217-88r_pic5_by_robert_evans.jpg?direct&300|}} {{:techtalk:ih:oil:xr-750_oil_pump_body_26217-88r_pic6_by_robert_evans.jpg?direct&300|}} \\
-This is a used pump showing the covers and gears. ((pics by Flattracker94 of the XLFORUM https://www.xlforum.net/forum/sportster-motorcycle-forum/sportster-motorcycle-era-specific-and-model-specific/xr-sportster-motorcycle-talk-xr750-xr1000-xr1200/xr-750/187566-xr750-engine-from-rag-to-ripper/page4)) \\
 {{:techtalk:ih:oil:1988-up_xr-750_oil_pump_pic1_by_flattracker94.jpg?direct&400|}} \\
 {{:techtalk:ih:oil:1988-up_xr-750_oil_pump_pic2_by_flattracker94.jpg?direct&400|}} {{:techtalk:ih:oil:1988-up_xr-750_oil_pump_pic3_by_flattracker94.jpg?direct&400|}} \\
 {{:techtalk:ih:oil:1988-up_xr-750_oil_pump_pic4_by_flattracker94.jpg?direct&400|}} {{:techtalk:ih:oil:1988-up_xr-750_oil_pump_pic5_by_flattracker94.jpg?direct&400|}} \\
+And here is the aluminum pump body (26217-88R): \\
+This is just the body without upper and lower covers. ((photos courtesy of ROBERT EVANS)) \\
+{{:techtalk:ih:oil:xr-750_oil_pump_body_26217-88r_pic1_by_robert_evans.jpg?direct&300|}} {{:techtalk:ih:oil:xr-750_oil_pump_body_26217-88r_pic2_by_robert_evans.jpg?direct&300|}} {{:techtalk:ih:oil:xr-750_oil_pump_body_26217-88r_pic3_by_robert_evans.jpg?direct&300|}} \\
+{{:techtalk:ih:oil:xr-750_oil_pump_body_26217-88r_pic4_by_robert_evans.jpg?direct&300|}} {{:techtalk:ih:oil:xr-750_oil_pump_body_26217-88r_pic5_by_robert_evans.jpg?direct&300|}} {{:techtalk:ih:oil:xr-750_oil_pump_body_26217-88r_pic6_by_robert_evans.jpg?direct&300|}} \\
 ====== Feed Bypass System ======
 ===== 1958-1968 KR, KRTT, KHRTT, XLR, XLRTT and 1970 Iron XR-750 Pump =====
@@ Line 157: / Line 152: @@
 {{:techtalk:ih:oil:1958-1971_kr-750_krtt_xlr_xr-750_xlrtt_oiling_paths_by_hawghd1.jpg?direct&400|}} \\
-====== Oil Line Diagrams ======
-Overall line diagrams showing general factory locations. These do not show later factory mods. \\
-===== 1970-1971 XR-750 =====
-{{:techtalk:ih:oil:1970-1971_xr-750_oil_hose_diagram.png?direct&600|}} ((drawing by Hippysmack)) \\
-====== 1975-1987 XR-750 ======
-{{:techtalk:ih:oil:1975_xr-750_oil_hose_diagram_by_hippysmack.png?direct&600|}} ((drawing by Hippysmack)) \\

Trace: • REF: Tools - 144

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