IH: Primary Drive & Clutch


Primary Design

Primary Chain Tensioner

77 XLH with 86-90 Primary Chain
Tensioner & Spring (40019-86) 1)

Primary Chain Tensioner Upgrade Kit (1977-up)

The HD kit is part number (39967-77A) for use on 1977-up XL, XLCH and XLS models.
Note: the V-Twin version of this kit comes with he adjusting screw that goes through the case along with the washers and locknut (not included in the HD kit).
Click Here to go the INSTRUCTIONS page in the Sportsterpedia, click on the “Y” next to instruction sheet for this kit (J00088) to download it.

The HD kit includes;

  • (1) Tensioner
  • (1) Pivot stud
  • (1) 26/64“ steel washer
  • (1) Locknut
  • (1) Spring
  • (1) 3/8” washer

Primary Fill / Drain Holes


Engine Sprocket

1957-1966 XLH, 1958-1969 XLCH sprocket kick only (40288-58) has the rear mounting surface below face.
1967-1976 XLH, 1970-1976 XLCH sprocket (40235-70A) has a mounting surface protruding from the face.
1977-up (all) sprocket (40235-74) has a mounting surface protruding even farther with a larger seal diameter.
None of them are marked with part#s. 2)

Comparison pics: 3)


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