[[:techtalk:menu|{{  :techtalk:gototechnicalmenu.jpg|}}]]
====== IH: Primary Drive & Clutch ======
 
\\

====== Primary Design ======



====== Primary Chain Tensioner ======

|{{techtalk:ih:priclutch:77_xlh_w_86-90_chain_spring_tensioner_by_northern_bobber.jpg?direct&300|}}|
|  77 XLH with 86-90 Primary Chain \\ Tensioner & Spring (40019-86) ((photo by northern bobber of the XLFORUM https://www.xlforum.net/forum/sportster-motorcycle-forum/sportster-motorcycle-era-specific-and-model-specific/ironhead-sportster-motorcycle-talk-1957-1985/184451-primary-chain-adjuster-spring-install/page3?t=1980020&page=3))  |

===== Primary Chain Tensioner Upgrade Kit (1977-E1980) =====
==== Sub-Documents ====
  * [[techtalk:ih:priclutch02f|Installing Primary Chain Tensioner Upgrade Kit on 1977-E1980 Sportsters]]

This HD kit (39967-77A) was offered in 1981 as a replacement for use on 1977-E1980 Sportsters. \\
[[:techtalk:miscres:miscres08#primary_drive_clutch|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. \\
Note: the V-Twin version of this kit (18-3220) comes with the adjusting screw that goes through the case along with the washers and locknut (not included in the HD kit).\\

  * The original HD kit included the items below. Originally, just the tensioner shoe was in the kit without the shoe bracket. \\ Later HD kits added the shoe bracket, changed the thickness of the washers and reportedly deleted the copper washer from the kit (to be bought separately).
    * (1) Chain Tensioner (39975-80)
    * (1) Pivot stud (40018-77)
    * (1) 3/8" Steel washer (6379W), (25/64" steel washer in 1995 kit)
    * (1) Locknut (7775) 3/8"-24 x 7/16" x 9/16"
    * (1) Spring (40019-80)
    * (1) 3/8" Copper Washer (6033) 

Click on pic to enlarge: \\
{{:techtalk:ih:priclutch:1977-e1980_sportster_primary_chain_tensioner_upgrade_kit_39967-77a_by_fizzle.jpg?direct&400|}} ((photo by fizzle of the XLFORUM)) {{:techtalk:ih:priclutch:1977-later_copper_washer_6033_by_robisonmotorcycles.jpg?direct&400|}} ((photo by Robison Motorcycles)) \\

====== 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. ((mct496 of the XLFORUM https://www.xlforum.net/forum/sportster-motorcycle-forum/sportster-motorcycle-era-specific-and-model-specific/ironhead-sportster-motorcycle-talk-1957-1985/112326-a-photo-catalog-of-ironhead-parts/page22#post3148620)) \\

Comparison pics: ((photos by mct496 of the XLFORUM https://www.xlforum.net/forum/sportster-motorcycle-forum/sportster-motorcycle-era-specific-and-model-specific/ironhead-sportster-motorcycle-talk-1957-1985/112326-a-photo-catalog-of-ironhead-parts/page22#post3148620)) \\ 
{{:techtalk:ih:priclutch:1957-1985_sportster_engine_sprocket_comparison_pic1_by_mct496.jpg?direct&400|}} {{:techtalk:ih:priclutch:1957-1985_sportster_engine_sprocket_comparison_pic2_by_mct496.jpg?direct&400|}} \\

\\

[[:techtalk:menu|{{:techtalk:gototechnicalmenu.jpg|}}]]