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Technical: Sprockets
Jerry Raino

Sprockets

 

  1952 1953 1954
to 1688
1954
1689-up
1955 1956 1957 1958 1959 1960 1961 1962 1963 1964 1965 1966 1967 1968 1969
Sidevalve Engine Overhead Valve Engine
750 cc 888 cc 883 cc
Transmission Mainshaft Sprocket - Standard
35198-52
20 Tooth
                XLCH
[4]
XLCH XLCH XLCH XLCH XLCH XLCH XLCH XLH
XLCH
XLH
XLCH
XLH
XLCH
35205-52
21 Tooth
All All   All [1] All [2]                            
35205-52A
21 Tooth
            XL All XLH
[4]
XLH XLH XLH XLH XLH XLH XLH      
35205-54
22 Tooth
    All [1]   All [2] All                          
Transmission Mainshaft Sprocket - Optional
35205-52A
21 Tooth
                                XLH
XLCH
   
Rear Wheel Sprocket
41473-54
49 Tooth
    All [3] All All All                          
41471-30
51 Tooth
All All All [3]       All All All All All All All All All All All All All

Notes:

  1. Discussed under Transmission Mainshaft Sprocket.
  2. Conflicting factory documentation - discussed under Transmission Mainshaft Sprocket.
  3. Conflicting factory documentation - discussed under Rear Wheel Sprocket.
  4. Discussed under Transmission Mainshaft Sprocket.

Transmission Mainshaft Sprocket

In 1954, there was a mid-year change to the gearing starting at 54 KH 1689. The change to the transmission mainshaft sprocket is well-documented and consistent in the parts books.. The Rider Handbook (prepared before the start of the model year) shows 22 tooth, and this is consistent with all the Spare Parts Catalogs, which show 22 tooth up to motor No. 1688, and then a mid-year change to 21 tooth from motor No. 1689 to the end of the year.

For 1955, we have conflicting information. Which is correct? You be the judge.

The Case For 21 Tooth

  1. The 1956, 1957, 1959 and 1963 Spare Parts Catalogs all show 21 tooth.
  2. Arguendo, the Harley tech writers incorrectly carried forward the 22 tooth information from the 1954 Rider Handbook to the 1955 edition.

The Case For 22 Tooth

  1. The 1955 Rider Handbook shows 22 tooth.
  2. Arguendo, the Harley tech writers incorrectly carried forward the 21 tooth information from the 1954 parts catalog to the 1955 and subsequent editions.

For the Sportster models, the parts books list many different sprockets as available for each year and model. What came stock, and what "fit" as replacements? Consulting the Service Manuals gives us a clear picture of which sprocket came stock on the bikes. The 1959 Rev 11-61 manual covers 1957 through 1962 Sportsters, while the 1969 manual covers 1959 through-1969 Sportsters. These manuals agree. The chart above shows only the stock sprockets.

Rear Wheel Sprocket

In 1954, there was a mid-year change to the gearing starting at 54 KH 1689. The change to the transmission mainshaft sprocket is well-documented and consistent. However, for the the rear wheel sprocket, we have conflicting information. Which is correct? You be the judge.

The Case For 49 Tooth All Year

  1. The 1954 Rider Handbook shows 49 tooth
  2. The 1954 Spare Parts Catalog shows 49 tooth for all 1954 KH
  3. The 1956 Spare Parts Catalog shows 49 tooth for all 1954 to 1956 KH
  4. The 1957 and later parts books show the 51 tooth for 1954 to 1956 Model KH from motor number 1689 up, but they are silent for 1954 KH up to 1968. This silence is significant.
  5. Arguendo, the Harley tech writers confused the changes in the mainshaft sprocket with the changes in the rear wheel sprocket, and incorrectly added the verbage "from motor No. 1689 up" for the rear wheel sprocket in the 1957 edition. This error was carried forward to subsequent editions. If you remove this verbage, then all the parts books agree on 49 tooth.

The Case For A 51 / 49 Tooth Split At motor No. 1689

  1. The 1957 and later parts books show the 49 tooth for 1954 to 1956 Model KH from motor number 1689 up. This signifies that there was a change at 1688/1689. Since the later 1954's had 49 tooth, the early ones must have had 51 tooth. The omission of the "up to 1688" information is unfortunate.
  2. The 1952 and 1953 K Models had 51 tooth. It is not unreasonable to believe that 51 tooth was continued into early 1954.
  3. Arguendo, It is possible that in 1957, the Harley tech writers discovered the error in the 1954 and 1956 parts books, and attempted to correct it. Unfortunately, they left out the information for the "up to 1688", leaving the reader to infer that the 1952-1953 sprocket was used.

It appears that we can not definitively resolve the two discrepancies without a consensus of original, unmolested examples of 1954 and 1955 KHs.

Rider Handbooks

The Rider Handbooks list the sprockets for each year/model. Keep in mind that the Rider Handbooks were prepared well in advance of the new model year release, so they show what was planned for the new year. Late pre-production changes, and changes made during the year, are not reflected. Here is a recap for the earlier years.

Year 1952 1954 1955 1956 1957
Motor 30 30 ? ? 34
Clutch 59 59 ? ? 59
Transmission 21 22 22 ? 34
Rear Wheel 51 49 49 ? 51

Service Manuals

The Service Manuals also provide a list of sprockets. For the early Sportsters, the 1959 (Rev 11-61) and 1969 Service Manuals document the range of Sportsters through 1969. Keep in mind that the Service Manuals were only issued every X years, so they may miss some small changes in the intervening years. However,

1959
Service
Manual
Rev. 11-61
1969
Service
Manual

Note that in typical Harley-Davidson style, the 1969 headings are a little confusing. It would have been much clearer if they read:

1966 & Earlier
XL-XLH
(Standard)
-and-
1967 XLH-
XLCH
(Optional)
1966 & Earlier
XLCH
(Standard)
-and-
1967 & Later
XLH-XLCH
(Standard)

Spare Parts Catalogs

Spare Parts Catalogs ("Parts Books") were issued annually. Keep in mind that the Spare Parts Catalogs were designed to assist the dealer to find replacement parts that would physically fit and function from his stock, not to document what originally came on the bike. Thus, they often specify functional replacements – usually the -A, -B kind of parts. A bright point is that they were typically issued late in the model year, so they often reflected mid-year changes. A dim point is that they are notoriously inaccurate, particularly with the illustrations.

1954 Spare Parts Catalog
35205-52 Transmission Mainshaft Sprocket – 21 tooth 52 & 53-Model K & KK,
54-Model KH from Motor no. 1689 up
35205-54 Transmission Mainshaft Sprocket – 22 tooth 54-Model KH to Motor No.1688 incl.
41471-30 Rear wheel sprocket [51 teeth] 52 & 53 K & Model KK
41473-54 Rear wheel sprocket [49 tooth] 54-Model KH
1956 Spare Parts Catalog
35205-52 Transmission Mainshaft Sprocket (Replaced by 35205-52A)
35205-52A Transmission Mainshaft Sprocket – 21 tooth 52 & 53-Model K & KK,
54 & 55-Model KH from Motor no. 1689 up
35205-54 Transmission Mainshaft Sprocket – 22 tooth 54-Model KH to Motor No.1688 incl.,
56-Model KH
41471-30 Rear wheel sprocket [51 teeth] 52 & 53 K & Model KK
41473-54 Rear wheel sprocket [49 teeth] 54 to 56
1957 Spare Parts Catalog
35205-52A Transmission Mainshaft Sprocket – 21 tooth 52 & 53-Model K & KK,
54 & 55-Model KH from Motor no. 1689 up,
57 Sportster
35205-54 Transmission Mainshaft Sprocket – 22 tooth 54-Model KH to Motor No.1688 incl.,
56-Model KH
41471-30 Rear wheel sprocket – 51 Tooth 52 & 53 K & Model KK,
57 Sportster
[ Note: Silence ] [ 54 Model KH to motor No. 1688 ]
41473-54 Rear wheel sprocket – 49 Tooth 54 to 56 Model KH from motor number 1689 up
1959 Spare Parts Catalog
35198-52 Transmission Mainshaft Sprocket – 20T 59 - Sportster CH
35205-52A Transmission Mainshaft Sprocket – 21T 52 & 53-Model K & KK,
54 & 55-Model KH from Motor no. 1689 up,
57 to 59 All Sportsters except 59-CH
35205-54 Transmission Mainshaft Sprocket – 22T 54-KH ( below engine no. 54KH-1689);
56-KH
41471-30 Rear wheel sprocket – 51 Tooth 52 & 53 K & Model KK,
57 to 59-All Sportster
[ Note: Silence ] [ 54 Model KH to motor No. 1688 ]
41473-54 Rear wheel sprocket---49 Tooth 54 to 56 Model KH from motor number 1689 up
1963 Spare Parts Catalog
35197-52 Transmission Sprocket – 19T 53 to 56 - K, KH
35198-52 Transmission Sprocket – 20T 59 to *--XLCH
35205-52A Transmission Sprocket – 21T 53-K; 54 & 55 - KH (above engine no. 54KH-1689);
57 & 58XL, XLH, XLCH; 59XLH,
60 to *--XLH, XLCH
35205-54 Transmission Sprocket – 22T 54-KH ( below engine no. 54KH-1689);
56-KH
41471-30 Rear wheel sprocket – 51 Tooth 53 K & Model KK, 57 to * --XL, XLH, XLCH
[ Note: Silence ] [ 54 Model KH to motor No. 1688 ]
41473-54 Rear wheel sprocket---49 Tooth 54 to 56 Model KH (above engine no. 54KH-1689)