All part numbers were gathered from period specific Sportster parts catalogs from 1957-1985 including supplement and updated catalogs.

Year Model	Part Number	For Kickstart?	Casting Number	Notes
1952-E1954 K Models	34876-52 1)	Yes	34874-52
Additional notes	It is believed the MoCo made a running change in mid 1954 when they changed worm gears. 2) The sprocket covers were sold as “complete”. So the new worm gear should have been installed in a new cover part#.
L1954-1956 K Models	34876-52A 3) 4)	Yes	34874-52	Replaced by 34876-52B (1957) Replaced by 34876-57 (1958) Used 34876-52A (1959-on)
1957 XL	34876-52B 5)	Yes		Replaced by 34876-57 (1958) Replaced by 34872-57A (1970) 6)
Additional notes	See Pic section below.
1958-1962 XL/XLH/XLC/XLCH	34876-57 7)	Yes	34874-52A	Replaced by 34872-57 (1963) Replaced by 34872-57A (1970) 8)
1963-1966 XLH/XLCH and 1967 XLCH	34872-57 9) 34872-57A	Yes	34874-52A 74-52	Replaced by 34872-57A For 1967 XLCH only (1968) 10) For all models (1970)
1967 XLH	34871-67 11)	Yes		Replaced by 34871-67A (1969) Replaced by 34871-67B (1970)
1967-1970 XLH	34871-67B 12)	Yes	79-67B	Offered in 1971
1968-1969 XLH	34869-68 13)	No
1968-1969 XLCH	34872-57A 14)	Yes	74-52
1970 XLH	34869-70 15)	No	79-67B
1970 XLCH	34872-70 16)	Yes
1971-1972 XLH	34870-71 17)	No	34879-71	Polished.
1971-1972 XLH	34871-71 18)	Yes	34879-71	Polished
1971-1972 XLCH	34872-71 19)	Yes	34879-71	Polished. Replaced by 34872-71 (1975)
1973 XLH	34870-73 20)	No	34879-71	Black. Kick cover 34871-71 (offered 1976)
1973 XLCH	34872-73 21)	Yes		Black
1974 XLH	34870-71 22)	No	34879-71	Polished. Kick cover 34871-71 (offered 1976)
1974 XLCH	34872-71 23)	Yes		Polished
1975-1976 XLH	34868-75 24)	No	34879-71	Kick cover 34871-71 (offered 1976)
1975-1976 XLCH	34896-75 25)	Yes	34879-71
1977-1978 XL/XLH	34870-75 34870-75A	No	34879-75 or 34876-75 34876-75A	Outer cover Replaced by 34870-75A (-78A cat)
1977-1978 XLCH	34872-75	Yes	34879-75	Outer cover
1977-1978 XL/XLCH	34893-75	N/A		Inner cover
1979 XLH	34863-79 26)	No	34879-79A	Outer cover
E1979 XLCH	34872-79 27)	Yes	34879-79A	Polished outer cover
1979 XLS	34870-79 28)	No	34879-79A	Outer cover
1979 XLH/XLCH/XLS	34899-79 29)	No	None	Inner cover
1980 XLH	34911-80 30)	No		Polished cover. Replaced by 34918-81 (1983)
1980 XLS	34912-80 31)	No		Black cover. Replaced by 34915-81 (1982) Replaced by 34915-81A (1984)
E1981-1982 XL	34918-81 32)	No		Polished cover. Replaced by 34918-81A (1984)
L1981-1985 XL	34911-81 33)	No		Polished cover. Replaced by 34918-81A (1985)
E1981 XLS	34915-81 34)	No		Vivid black cover. Replaced by 34915-81A (1985)
L1981-1982 XLS	34912-81 35)	No		Black cover
1983-1984 XLS	34911-81 36)	No		Polished cover
1983-E1984 XLX	34908-83 37)	No		Aluminum finish cover
L1984-1985 XLX	34908-83A 38)	No		Painted cover

Cover part# change between 1957 and 1958:
Cover (34876-52B) shows up for the first time in the -57 parts catalog for 1957 XLs and replacement for all 1952-1956 K Models.
However, the -58 parts supplement catalog labels the -52B cover as “not used, Replaced by 34876-57”.
And the -58 catalog also shows the 34876-52A cover as replacement for K Models, not the -52B cover.

Sprocket Cover part# (34876-57), with kickstarter. The casting number is (34874-52A).
Visual changes:
The angle of the worm gear grease (zerk) fitting changed to (angled forward 1:00) as opposed to the vertical position on the K Model covers.
The grease fitting is threaded into the boss.
Also the grease (zerk) fitting position for the kick starter crankshaft was moved to the (9:00) position.
A boss is cast into the cover at the (9:00) position as extra strength for the grease fitting which is pressed in.
The pin stop for the worm gear is simply pressed into a hole drilled through the cover at an angle.
The center cavity under the bar on the cam cover side resembles the back side of an arrow.

^{39) 40)}

^{41) 42)}

Sprocket Cover part# (34872-57), with kickstarter. The casting number is (34874-52A). Visual changes:
The grease (zerk) fitting position for the kick starter crankshaft was moved to the forward side of the bushing hole (1:00).
A long angled boss was added off the crankshaft bushing bore for the new grease fitting location.
The 1962-previous boss is still present at the (9:00) position but it is not drilled out for a fitting.
The pin stop for the worm gear is pressed into a hole drilled through the cover at an angle.
The center cavity under the bar on the cam cover side resembles the back side of an arrow.

Sprocket Cover (34869-70), without kick starter.
Click on a pic to enlarge

^{43) 44)}

Additional pics

^{45) 46)}

Sprocket Cover (34871-67B), with kickstarter. This cover was sold in 1971 as a replacement for 1967-1970 XLH models.
Click on a pic to enlarge ⁴⁷⁾

Sprocket Cover (34870-71), polished, without kick starter.
Click on a pic to enlarge ⁴⁸⁾

Sprocket Cover (34870-73), black, without kick starter.
Click on a pic to enlarge ⁴⁹⁾

Sprocket Cover (34868-75), polished, without kick starter.
Click on a pic to enlarge: ⁵⁰⁾

Original Outer Sprocket Cover (34870-75) for 1977-1978 XL/XLH, polished, without kick starter.
Click on a pic to enlarge: ⁵¹⁾

Replacement Outer Sprocket Cover (34870-75A) for 1977-1978 XL-XLH, polished, without kick starter. ⁵²⁾

Outer Sprocket Cover(34863-79), polished, without kickstarter.
Click on a pic to enlarge: ⁵³⁾

Outer Sprocket Cover (34872-79), polished, with kichstarter.
Click on a pic to enlarge: ⁵⁴⁾

Original Outer Sprocket Cover(34870-79), factory painted silver, without kickstarter.
Click on a pic to enlarge: ⁵⁵⁾

An Inner Sprocket Cover (34899-79) was used for all 1979 model Sportsters. The pic below is of a used inner cover. ^{56) 57)}