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====== IH: Primary Drive & Clutch ======
 
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====== 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 Fill / Drain Holes ======
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====== 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|}} \\

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