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Generators

Five generators were used on the K models and Sportsters from 1952 through 1969. As with everything Harley, there were minor improvements made throughout the years. The Spare Parts Catalogs must be consulted to find every little change.

Volt	Model	Part #	Used On	Also Used On
6 Volt	Model 52K	29982-52	1952-1956 K/KH; 1957 XL	—
	Model 58	29975-58	1958-1960 XLH, XLCH	Big Twin, Servi Car
	Model 61	29975-58A	1961-1964 XLH, XLCH	Big Twin, Servi Car
12 Volt	Model 65	29975-65	Early 1965 XLH, XLCH	Big Twin
	Model 65A	29975-65A	Late 1965 to 1981 XLH, XLCH	Big Twin

Model 52K

The Model 52K was only used on the K/KH and 1957 Sportster. It had an open aluminum housing on the commutator end. A steel cover covered the the opening, and had holes in it where the regulator mounted. The drive gear was affixed with a roll pin. The Model 52K shares many parts with the venerable Model 32E, such as armature, field coils, and aluminum housing.

Model 52

Yes, VIRGINIA, there is a Model 52 generator. It was used on Panheads, but NOT on K-models.

Model 58

The Model 58 was used across the Harley line, except for the Hummer and Model 165. It had a longer center body than the 52K. The commutator cover was steel, and had an oil cup to allow oiling of the bronze bushing. A spring-loaded band covering the brushes. The regulator mounted on a bracket which was attached to the commutator cover. A chrome-plated outer cover was optional on the XLH.

Model 61

The Model 61 had a roller (needle) bearing instead of a bushing on the commutator end. The End Cover, armature and the bearing are the only differences. The end cover does not have an oil cup.

Model 64

Yes, VIRGINIA, there is a Model 64 generator. The first 12 volt Harley was the 1964 Servi-Car, the only year/model on which the Model 64 generator was used. The Servi went to an alternator in 1965. Sorry, but we know nothing else about these.

Model 65

The Model 65 used a different armature and field coils to produce 12 volts. Otherwise, the Model 65 is nearly identical to the Model 61. This generator was only used for about six months, since there was a problem with sticking brushes - the paper insulator used under the insulated brush holder would swell, causing the brush to stick. A chrome-plated outer cover was optional on the XLH.

Model 65A

The Model 65A solved the problem by rotating the brush plate 180 degrees to put the positive (insulated) brush on the topside to keep it dry. This required swapping the A and F terminals. The Model 65A can be distinguished by the A terminal on the left, looking from the commutator end. A chrome-plated outer cover was optional on the XLH.

Model 65B

The Model 65B was used from 1982 until early 1984. It was made in Japan by Hitachi, and shares no parts with the other generators. Out of scope for our interests, but listing it here provides closure to the generator era.

Drive Gears

A variety of drive gears were used to adapt the generator to the different model bikes, and for differences within the models.

I have noticed that many sellers, particularly on-line sellers, misrepresent the part number / fitment of the gears. It is common to see a 31070-58 gear being sold as 31071-58 and fitting Sportster. The 31070-58 gear does not have an oil slinger, and fits Big Twins. The 31071-58 does have a oil slinger and fits Sportsters. There are many similar looking gears, and this section is intended to help the unwary figure out which gear fits their bike.

Drawing 1

Drawing 2

Part #	Dwg	Teeth	Shaft Style	A	B	C	D	E	F	P	Notes
K and Sportster
31071-52	1	14	Uses pin	1-1/32	15/16	5/8	7/32	23/64	1-5/8	Yes	Used on: 1952-1956 K/KH [ F dim = 1.635]
31071-52A	1	14	Uses pin			???	???	–	—	Yes	Used on: 1957 XL
31071-58	1	14	Threaded	1	11/16	5/8	9/32	5/16	1-19/32	No	Used on: 1958-1962 XL, XLH, XLCH
31073-63	2	14	Threaded			5/8	???	–	—	No	Used on: 1963-19xx XLH, XLCH    with 31067-63, ‘Washer, oil separator’
31073-63A	2	14	Threaded			5/8	???	–	—	No	Used on: 19xx-up XLH, XLCH    with 31067-63, ‘Washer, oil separator’
Adapt Model 58, 61, 65, 65A to Other Models
31070-58	2	13	Threaded	31/32	11/16	5/8	1/4	–	—	No	Used on: Big Twins 1958 - 1969
31075-58B	1	14	Threaded					–	—	No	Used on: 58-64 ServiCar
Similar Looking Gears
31070-30	2	14	Uses pin	1.000		???	???	???		Yes	Used on: 1936-1944 OHV
	2	14	Uses pin	1.022		???	???	???		Yes	Used on: 1945-1957 OHV
31071-37	1	14	Uses pin	1.000		???	???	???		Yes	Used on: 1937-1957 W " G; 1937-1948 74 " 80 Sidevalve

Breather Sealing Items & Recap

Another source of confusion is the items which separate gearcase air from oil to prevent too much oil coming out of the breather tube.

Harley-Davidson added to the confusion. It appears that in earlier years they sold the “25265-52 Bushing, oil separator assembly”, which included the 25270-52 Seal ring, but in later years, these parts were sold separately.

So here is a list of the items from generator to cam cover arranged by years.

Years	Generator	Gear	Washer, oil separator	Seal Ring	Spring	Bushing, oil separator	Deflector, oil separator	Gear Case Cover
1952-1956	Model 52K	31071-52	—	25270-52	25287-37	25265-52	—	25200-52 [1]
1957	Model 52K	31071-52A [2]	—	25270-52	25287-37	25265-52	—	25200-57
1958-1960	Model 58	31071-58	—	25270-52	25287-37	25265-52	—	25200-57
1961-1962	Model 61	31071-58	—	25270-52	25287-37	25265-52	—	25200-57
1963-1964	Model 61	31073-63 [3]	31067-63	—	—	—	25265-63	25200-57

1. When the -52A gear case cover appeared is unknown. The 1957 parts book shows the -52 for 1952 to 1954. The 1963 book shows -52A.
2. When the -52A gear appeared is unknown. The 1954 parts book lists the -52. The 1957 book lists the -52A.
3. There is a -63A gear, but it appears to have appeared later than 1965.