Harley-Davidson Big Twin OHV, Big Twin SV, 45, K & Sportster
Oil Pump Data and Comparison

Big Twin OHV Oil Pump Gears, sorted by application

Year

Engine

Pump speed

Gear

Type

Thick.

Gear ID

Area; Speed
× scav. %

Comment

Part Nº

1936-47

knucklehead

5 tooth pump gear
÷ 25 tooth pinion gear
= 20% (1/5th) engine speed; “5:1” ratio

feed

driven

.250”

.422”

.248”

keyway slot

26315-36

idler

.342”

plain

26317-36

scav.

driven

.500”

.422”

.495”
200%

keyway slot

26320-36

idler

.342”

plain

26325-36

1948-61

panhead

feed

driven

.380”

.422”

.376”

keyway slot

26315-48

idler

.342”

plain

26317-48

scav.

driven

.500”

.422”

.495”
132%

keyway slot

26320-36

idler

.342”

plain

26325-49

1962-67

panhead,
shovelhead

feed

driven

.380”

.422”

.376”

keyway slot

26315-48

idler

plain

26317-62

scav.

driven

.500”

.495”
132%

keyway slot

26320-36

idler

plain

26326-62

1968-72

shovelhead

feed

driven

.4375”

.433”

keyway slot

26315-68

idler

plain

26317-68

scav.

driven

.625”

.619”
143%

keyway slot

26320-68

idler

plain

26326-68

1973-85

6 tooth pump gear
÷ 24 tooth pinion gear
= 25% engine speed (1/4th) engine speed; “4:1” ratio

feed

driven

.4375”

.433”

keyway slot

26315-68

idler

plain

26317-68

scav.

driven

.625”

.619”
143%

keyway slot

26320-68

idler

plain

26326-68

1954-89

Baisley

8 tooth pump gear ÷ 24 tooth pinion gear = 33% engine speed, “3:1” ratio

11 tooth pump gear ÷ 22 tooth pinion gear = 50% engine speed, “2:1” ratio

45, UL, K & Sportster Oil Pump Gears, sorted by application

Year

Engine

Pump speed

Gear

Type

Thick.

Gear ID

Area;
Speed × scav. %

Comment

Part Nº

1937-73

45 1937-73, U-Series 1937-48

5 tooth pump gear
÷ 25 tooth pinion gear
= 20% engine speed

feed

driven

.250”

.422”

.248”

keyway slot

26315-36