• Breather Valves (1957-Up) (list of breather valve changes)
• Further Study of the Timed Breather Valve

The parts charts below represent what each oil pump part number should have looked like when new.

• There are 3 basic pumps & 2 basic plumbing styles ¹⁾
  1. Both feed and return are drilled passages in the right crankcase (57-66 all) & (67-69 xlch)
  2. Only return drilled thru case. feed goes from tank to pump by external hose. (67-69 xlh) & (70-76 all)
• With the correct knowledge any 57-76 pump, or parts of them can be mated to any 57-76 cases. But the combos can get confusing. ²⁾
• The stock slot in pre & post -72 pump bodies is .345“ ³⁾
• The stock slot in pre -72 pump gear is .375” ⁴⁾
• The stock slot in post -72 pump gear is .625“ ⁵⁾

• There are (3 variations) and these all use 16t gear sets and style 1 plumbing ⁶⁾
• The production changes made during its run: ⁷⁾
  • 1957-E1958: Baseline pump that all others came from.
    It has no oil seal and uses a snap ring and a full profile woodruff key at the scavenge gear.
  • L1958-1959: The body is now machined for an oil seal.
  • 1960-E1962: The retaining ring at the scavenge gear was replaced by half moon retainers.
    The scavenge drive gear is counter-bored for these half moons and the woodruff key is shortened so it won't interfere with the half moons.

• Feed Gears:
  O.D. (1.115” OD) ⁸⁾
  Width (.185“) ⁹⁾
• Return Gears:
  O.D. (1.115” OD) ¹⁰⁾
  Width (.343“) ¹¹⁾
• Driven Gear:
  Center hole I.D. (.422”) ¹²⁾
• Idler Gear:
  Center hole I.D. (.422“) ¹³⁾

Pump assembly (26203-52C) is basically the same as the 1956 KH model oil pump (-52B). Pump speed is 1/2 engine RPM.
1952-1955 K Model pumps have a feed bypass system built into them which was deleted in the 1956 pump version.
The 1956-1958 pump body has the rear port cast shut starting in 1956 (as this is where the 52-55 feed bypass was installed).

The 1957 pump has the same pump body, 16T gears, covers and breather gear with a new check ball spring and oil switch nipple.
1952-E1958 pump bodies were not machined for an oil seal between the feed and return gears.
The L1958 pump body was the first to be machined for the seal between the feed and return gears (no part number change).

1957-1958 Version Parts List:

Oil Pump Assembly	Oil Pump Casting#	Oil Pump Body	Upper Cover / Breather Tower	Lower Cover Plate	Oil Pump Drive Gear	Feed Gear (driver)	Feed Gear (idler)	Return Gear (driver)	Return Gear (idler)
26203-52C	26215-52	26217-56	26241-52	26250-56	26318-37	26323-52	26322-52	26320-56	26326-52
Idler Gear Shaft	Breather Gear	Feed Gear Lock Pin	Return Gear Woodruff Key	Breather Shaft Ret Ring	Oil Pump Check Ball (with tail)	Oil Pump Check Spring	Oil Pump Switch Nipple	Oil Pressure Switch - exc. XLC/XLCH	Oil Switch Nipple Plug (XLCH)
26327-52	26331-56	603	26347-15	11002	26400-52A	26364-57	26420-57	26550-57	45830-48
Pump Gasket Lower	Pump Gasket Upper	Pump Gasket Mounting	Oil Pump Seal (L1958)
26258-52	26259-52	26256-52	26227-58

Click on any pic to enlarge: ¹⁴⁾

Pump assembly (26203-52D) went through several changes without an assembly part# change. Pump speed is 1/2 engine RPM.
All versions of this pump use 16T gears.
Pump body (26217-56A) was used from L1958-E1962. It is the same as 56KH to E58 XL body but machined for the seal between the feed and return gears.

1959-E1960 Version:
1959 pump is the exact same as the L58 pump with the only change being the oil switch check ball (with tail) was replaced with a 3/8” round ball.
E1960 pump additons include an oil pressure switch rubber boot except for XLC and XLCH models and a new oil pressure switch.
In L1960, a breather and scavenger gear set (26330-56) was sold to update 56-E62 K Model and Sportster pumps to the L1960 pump configuration.

1959-E1960 Version Parts List:

Oil Pump Assembly	Oil Pump Casting#	Oil Pump Body	Upper Cover / Breather Tower	Lower Cover Plate	Oil Pump Drive Gear	Feed Gear (driver)	Feed Gear (idler)	Return Gear (driver)	Return Gear (idler)
26203-52D	26215-52	26217-56A	26241-52	26250-56	26318-37	26323-52	26322-52	26320-56	26326-52
Idler Gear Shaft	Breather Gear	Feed Gear Lock Pin	Return Gear Woodruff Key	Breather Shaft Ret Ring	Oil Pump Check Ball (no tail)	Oil Pump Check Spring	Oil Pump Switch Nipple	Oil Pressure Switch - exc XLCH (59)	Oil Pressure Switch - exc XLCH (60)
26327-52	26331-56	603	26347-15	11002	8866	26364-57	26420-57	26550-57	16551-39B
Oil Switch Rubber Boot (60)	Oil Switch Nipple Plug (XLCH)	Pump Gasket Lower	Pump Gasket Upper	Pump Gasket Mounting	Oil Pump Seal
26553-58	45830-48	26258-52	26259-52	26256-52	26227-58

Pump body (26217-56A). Click on any pic to enlarge: ¹⁵⁾

L1960 pump (26203-52D), the retaining ring at the scavenge gear was replaced by the split washer retainer.
The scavenge drive gear is counter-bored for the split washer and the return woodruff key is shortened so it won't interfere with the split washer. ¹⁶⁾
This pump uses the same body as E58-E60 pumps.

1961 changes:
2 dowels (9095, standard mainshaft roller bearing - .1562“ x .615) were added for replacements to the 61-up pump body.
A new feed gear solid drive pin (240, actually a hardened needle roller ¹⁷⁾ ) used on 1961-1971 breather valve shafts.

L1960-E1962 Version Parts List:

Oil Pump Assembly	Oil Pump Casting#	Oil Pump Body	Pump Body Dowel (2)	Upper Cover / Breather Tower	Lower Cover Plate	Oil Pump Drive Gear	Feed Gear (driver)	Feed Gear (idler)	Return Gear (driver)
26203-52D	26215-52	26217-56A	9095	26241-52	26250-56	26318-37	26323-52	26322-52	26320-60
Return Gear (idler)	Idler Gear Shaft	Breather Gear	Feed Gear Lock Pin (60-down)	Feed Gear Lock Pin (61-up)	Return Gear Woodruff Key	Breather Shaft Split Washer	Oil Pump Check Ball (no tail)	Oil Pump Check Spring	Oil Pump Switch Nipple
26326-52	26327-52	26331-60	603	240	26340-36	26341-37	8866	26364-57	26420-57
Oil Pressure Switch - all (ex XLCH)	Oil Switch Nipple Plug (XLCH)	Oil Switch Rubber Boot	Pump Gasket Lower	Pump Gasket Upper	Pump Gasket Mounting	Oil Pump Seal
26551-39B	45830-48	26553-58	26258-52	26259-52	26256-52	26227-58

• There are (2 variations) and all these used 14t gears & scavenge sets got taller than the previous 16's were. ¹⁸⁾
• All use half moon retainers and the shortened woodruff key on the scavenge drive.
• All bodies made up to 1966 are for internal feed and scavenge plumbing (plumbing style 1).
  • In 1967, the rear of the body gets tapped for the external feed fitting for use on 1967-1969 XLH. This is when style 2 plumbing started.
  • Bodies tapped for style 2 were still used with the addition of a plug in the new rear hole on 1967-1969 XLCH (style 1 cases).

• Feed Gears:
  O.D. (.990”) ¹⁹⁾
  Width (.216“) ²⁰⁾
• Return Gears:
  OD (.990”)
  Width: (.375“) ²¹⁾
• Driven Gear:
  Center hole I.D. (.422”) ²²⁾
• Idler Gear:
  Center hole I.D. (.422“) ²³⁾

L1962-1966 XLH and L1962-1969 XLCH pump body (26216-62).
Made for feed inlet and return outlet on rear top of right case.

In L1963, an oil pressure switch terminal was added for parts replacement and the rubber boot over the switch was deleted.
In 1964, the oil pressure switch got a new part number (36551-39C) complete with fittings and a new oil pressure switch nipple (26569-58).
The 1967-1969 version was strictly sold for XLCH although the new 67 H pump will work on 67-69 CH models.
The XLH case changed in 1967 when they got electric start and the feed fitting is no longer on the XLH case.

L1962-1969 Version Parts List:

Oil Pump Assembly	Oil Pump Casting#	Oil Pump Body	Pump Body Dowel (2)	Upper Cover / Breather Tower	Lower Cover Plate	Oil Pump Drive Gear	Feed Gear (driver)	Feed Gear (idler)	Return Gear (driver)
26203-52E	26215-52	26216-62	9095	26241-52	26250-56	26318-37	26323-62	26322-62	26315-62
Return Gear (idler)	Idler Gear Shaft	Breather Gear	Feed Gear Lock Pin	Return Gear Woodruff Key	Breather Shaft Split Washer	Oil Pump Check Ball (no tail)	Oil Pump Check Spring	Oil Pump Switch Nipple	Oil Pump Switch Nipple (64)
26317-62	26327-52	26331-60	240	26340-36	26341-37	8866	26364-57	26420-57	26569-58
Oil Pump Switch - all except XLCH	Oil Pump Switch - all (64)	Oil Switch Nipple Plug (XLCH)	Oil Switch Rubber Boot	Oil Switch Terminal (L63)	Pump Gasket Lower	Pump Gasket Upper	Pump Gasket Mounting	Oil Pump Seal
26551-39B	36551-39C	45830-48	26553-58	26560-63	26258-62	26259-62	26256-52	26227-58

Click on any pic to enlarge: ²⁴⁾

1967-1971 XLH, 1970-1971 XLCH body (26216-62A) got a slanted vertical hole drilled through the feed channel to intersect with a horizontal hole drilled through the rear of the pump to redirect incoming oil from the case fitting to now come straight from the oil tank. The rear is threaded 1/8” x 27 NPS (straight pipe thread) for either a NPT (tapered) 3/8“ hose nipple to the oil tank or 1/8” pipe plug. The hose nipple was needed for 67-up XLH models due to the feed inlet fitting being deleted on top rear of the case. The pipe plug closes off rear feed intake for use on 67-69 XLCH models with the feed inlet fitting and return outlet on the rear top of the engine case.

The 1967 pump version (26204-67) was designed for the 67 XLH but could be used on XLCH also with the addition of a plug on the rear of the pump body.
With the feed hole in the XLH case now deleted, the original feed hole thru the upper cover is blocked off oon XLH models.
XLCH models can use this pump by removing the hose fitting and installing the pipe plug in the rear of the pump.
The original body plug shows up in the 1967 parts supplement catalog as (45831-48) which was replaced in the 1969 parts supplement to (45830-48).
From 1970-1971, this pump was sold for both XLH and XLCH. 70-up XLCH deleted the feed fitting on top rear of the case ( pump 26203-52E deleted).

1967-1971 Version Parts List:

Oil Pump Assembly	Oil Pump Casting#	Oil Pump Body	Pump Body Dowel (2)	Upper Cover / Breather Tower	Lower Cover Plate	Oil Pump Drive Gear	Feed Gear (driver)	Feed Gear (idler)	Return Gear (driver)
26204-67	26215-52	26216-62A	9095	26241-52	26250-56	26318-37	26323-62	26322-62	26315-62
Return Gear (idler)	Idler Gear Shaft	Breather Gear	Feed Gear Lock Pin	Return Gear Woodruff Key	Breather Shaft Split Washer	Oil Pump Check Ball (no tail)	Oil Pump Check Spring	Oil Pump Switch Nipple	Oil Pump Switch - all
26317-62	26327-52	26331-60	240	26340-36	26341-37	8866	26364-57	26569-58	36551-39C
Oil Switch Nipple Plug (XLCH)	Oil Switch Terminal	Rear Feed Line Fitting (XLH)	Rear Pump Body Plug (XLCH)	Pump Gasket Lower	Pump Gasket Upper	Pump Gasket Mounting	Oil Pump Seal
45830-48	26560-63	63533-41	45830-48	26258-62	26259-62	26256-52	26227-58

Click on any pic to enlarge: ²⁵⁾

These have (no variations) and go back to 16t gears and a snap ring with long key ²⁶⁾
Feed gears are the same as 1957-E1962 but the scavenge set is now wider again (wider than any of the previous sets).
Breather gear gets enlarged slots in it.
Body and breather housing get an extra hole (2 holes now) drilled in them for additional return capacity, cases also get extra matching hole. ²⁷⁾
Solid feed gear drive pin gets replaced by the hated roll pin.
Dowels between body and breather housing are now history.
The pump body got a new casting number suffix (-72).
Upper and lower gaskets changed back to their -52 counterparts.
L1972 change to oil check spring (26364-72).
Pump gears superceded thru the 1975 (-75) parts catalog supplement.

• Feed Gears:
  O.D. (1.115“ OD) ²⁸⁾
  Width (.185”) ²⁹⁾
• Return Gears:
  O.D. (1.115“)
  Width (.397”) ³⁰⁾
• Driven gear:
  Center hole I.D. (.422“) ³¹⁾
• Idler gear:
  Center hole I.D. (.422”) ³²⁾
• Breather timing:
  • Open 20-25 deg ATDC Front CYL ³³⁾
  • Close 85-90 deg ABDC Front CYL ³⁴⁾

1972-1976 Version Parts List:

Oil Pump Assembly	Oil Pump Casting#	Oil Pump Body	Upper Cover / Breather Tower	Lower Cover Plate	Oil Pump Drive Gear	Feed Gear (driver)	Feed Gear (idler)	Return Gear (driver)	Return Gear (idler)
26204-67A	26215-72	26214-72	26241-52	26250-56	26318-37	26323-52 26323-52A	26322-52 26322-52A	26315-72 26315-72A	26317-72 26317-72A
Idler Gear Shaft	Breather Gear	Feed Gear Roll Pin	Return Gear Woodruff Key	Breather Shaft Retainer Ring	Oil Pump Check Ball (no tail)	Oil Pump Check Spring (E72)	Oil Pump Check Spring (L72)	Oil Pump Switch Nipple	Oil Pump Switch - all
26327-52	26331-72	603	26347-15	11002	8866	26364-57	26364-72	26569-58	36551-39C
Oil Switch Nipple Plug (XLCH)	Oil Switch Terminal	Oil Switch FM Blade Terminal	Rear Feed Line Fitting (XLH)	Rear Pump Body Plug (XLCH)	Pump Gasket Lower	Pump Gasket Upper	Pump Gasket Mounting	Oil Pump Seal
45830-48	26560-63	9914	63533-41	45830-48	26258-52	26259-52	26256-52	26227-58

1972-1976 pumps have a number stamped on the front nipple (feed side). At this time it's not clear what these numbers indicate.
³⁵⁾

See also Check ball seat repair in the IH Oil Pump section of the Sportsterpedia.

The oil pump check ball is in the front of the oil pump. It's a spring and a steel ball set up.
The red area in the pic below is the spring & ball sit.

Used until mid 1958, the tail of check fits inside the hollow center guide bore of the fitting. ³⁶⁾
Note that there is no inner face seal surface on the fitting to further isolate the pressure switch port from the 'backside' of the check.

Are the early and later switch fittings interchangeable and function exactly the same? I prefer the bell shape of the early ones.

all ball check (L57-76) fittings are interchangeable. idk if 52-e57 (plunger check) will interchange. plunger check fittings are drilled to accept plunger 'tail'. ball check fittings are not drilled.

Of the 3 pumps, 57-e62, L62-71, and 72-76, two share the same feed gears. The e62< & the 72>. ³⁷⁾
These two pumps do not share the same check spring. The -72 spring is much stiffer.
72 is also the year the 4psi switch came out. Body check seat height remained the same all years.
A careful examination reveals the heavier spring can supply a higher pressure to switch by keeping ball seated.
When ball is seated, oil flow to motor is SHUT OFF. This last point is sumtin the “stretch the spring” crowd may want to re-read.
2psi switch (26551-39c)
4psi switch (26552-72)
If check closes (stretched spring) at a higher pressure than sender signals at, the lite stays off while flow to motor is stopped.
By stretching the 'idiot spring' the 'idiot' may shut off two thing at the same time– the idiot lite and the flow to motor.

³⁸⁾

There were 3 springs used from 52-76. ³⁹⁾
(52-56 also used a second valve- pressure relief).

1. 52-E57: (26363-36)
2. L57-E72: (26364-57)
   • Wire length: 1-15/64“ ⁴⁰⁾
   • Wire O.D.: ≈ 0.0250” ⁴¹⁾
3. L72-76 (26364-72)
   • Wire length: 1-7/16“ ⁴²⁾
   • Wire O.D.: ≈ 0.0250” ⁴³⁾

This is suppose to be a NOS 67 Pump Spring.
L = 1.215“ Wire Gauge = .024”

67 oil pump spring. 44)

52-E57 45)	(L) L57-E72 - (R) L72-76 46)	(Bottom) L57-E72 - (Top) L72-76 47)

• 1952-1955 production K Models and XR/XLR/KR racing (R) pumps are machined in the rear of the pump body for a feed bypass system.
  It consists of a tail ball and spring with a plug screw similar to the front oil switch nipple.
  The pump was line bored at an angle to the right (looking from top of pump) thru the vertical drilled bypass hole then thru to pressure side of the feed path.
  The bypassed feed oil runs North from the pump into a hole in the gearcase to fall on the cam floor for scavenging.
  The ID of the threaded hole in the pump rear is too big for the 1/8“ NPT fitting used on later models.
• 1956 KH, 1957-1966 XL/XLH and 1958-1969 XLCH had both feed and return fittings mounted on the top rear of the case.
  There was no feed bypass used on these models.
  But the MoCo used the same basic body, as they were still using it to service early K Models as well as early racing pumps.
  The hole in the rear of the 56-up KH and Sportster pump bodies was cast shut without the drilling /tapping and plug on these year pumps.
• 1967-1976 XLH and 1970-1976 XLCH deleted the top rear feed fitting and revised that cast shut hole for a feed oil re-route to the pump's rear side.
  The oil feed from the tank was now plumbed directly into the oil suction galley in the rear of the oil pump.
  An angled vertical hole was drilled from the feed side oil galley intersecting a horizontal hole drilled straight from the rear side of the pump.
  The rear hole is now threaded for an 1/8” NPT fitting.
  (either a 3/8“ hose fitting for models the pump was intended or an 1/8” pipe plug if used on previous year models).

Rear Hole Usage in Pics 49)

1972-1976 production K and Sportster models use inner (upper) pump oil pump cover (26241-52).
However, there were 3 different versions of this cover and all share the same original part number. The differences in versions are shown below.

The 2 different 16T gear breather housings side by side. 50)

Part# (26241-52).
This version, used on 14T gear pumps, deleted the hole in the cover for the early K model feed bypass.
Sold as replacement for 52-E62 K Model, Sportster oil pumps.
Breather tower slot width: (.345“) ⁵¹⁾ Note: To use this cover on 1952-1955 K Model pumps, remove body dowel pins and drill the hole for the feed bypass (if used).
It has the single return oil inlet hole. Sold as replacement for 1952-1971 K Model and Sportster oil pumps.

Click on any pic to enlarge. ⁵²⁾

Part# (26241-52).
This version, used on 16T gear pumps, deleted the hole in the cover for the early K model feed bypass.
It has 2 (double barrel) return oil inlet holes. Sold as replacement for 1952-1971 K Model and Sportster oil pumps.
NOTE: To use this cover on pre-1972 XL pumps, the body dowel pins have to be removed.
To use this cover on 1952-1955 K Model pumps, remove body dowel pins and drill the hole for the feed bypass (if used).
Breather tower slot width: (.345”) ⁵³⁾

Click on any pic to enlarge. ⁵⁴⁾

Outer cover (26250-56) was used on 1956 KH and 1957-1976 Sportster production models.
Also used on 1956-1987 KR, KHR, XR and XLR competition models.

⁵⁵⁾

The various breather gear shafts are machined for the shaft and drive gear fasteners shown below.
The roll pin is not bullet proof. It is rare, but they do fail.
The solid pin is a bullet proof factory part = good insurance.
Fastener List:

• 1952-1955 K Model pumps:
  • Used breather gear (26331-52) with a split washer retainer (26341-37) x 2.
  • Both the feed and scavenge drive gears are locked in with a roll pin (603).
• 1954 KH and 1957-E1960 Sportster pumps:
  • Used breather gear (26331-56) with the retainer “snap” ring (11002).
  • Feed drive gear is locked in with a roll pin (603).
  • Scavenge drive gear is locked in with a standard woodruff key (26347-15).
• L1960-1971 Sportster pumps:
  • Used breather gear (26331-60) with a split washer retainer (26341-37) x 2.
    The scavenge drive gear is counter-bored for the split washer (half moons).
  • Feed drive gear is locked in with a solid pin (240).
  • Scavenge drive gear is locked in with a shortened key (26340-36) so it won't interfere with the split washer.
• 1972-1976 Sportster pumps:
  • Used breather gear (26331-72) which went back to the retainer “snap” ring (11002).
    • Feed drive gear is locked in with a roll pin (603).
    • Scavenge drive gear is locked in with a standard woodruff key (26347-15).

Pin Specs:

• Roll pin (603) is a 3/32“ (.09375”) x 1/2“ roll pin. ⁶³⁾
  
• Solid pin (240) is a .094” x 1/2“ hardened 52100 steel bearing roller. ⁶⁴⁾
  

More often than not the solid pin was a slipfit in cross hole.65)	Here are the 2 pins side by side. 66)

⁶⁷⁾

1952-E1971 production Model K and Sportster pumps used 1/4”-20 x 1/4“-28 x 2-5/16” studs with lockwashers and nuts.
L1971-1976 production Sportster pumps used 1/4“-20 x 2” bolts and lockwashers.