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| techtalk:evo:transfinal01 [2025/08/14 01:28] – [Final Drive Sprocket - Stripped Splines] hippysmack | techtalk:evo:transfinal01 [2025/08/14 05:06] (current) – [Final Drive Sprocket - Stripped Splines] hippysmack |
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| **Causes of Stripped Splines**: \\ | **Causes of Stripped Splines**: \\ |
| This problem is usually caused by the lock screws and the main nut becoming loose. With even a little play, the pulley will rock on the shaft every time you open or close the throttle. This will cause wear on the splines no matter what material the pulley is made of. ((steelworker of the XLFORUM https://www.xlforum.net/forum/sportster-motorcycle-forum/sportster-motorcycle-era-specific-and-model-specific/frame-mount-evo-sportster-talk-1986-2003-models/163019-drive-pulley-number-2)) The stock pulley is made of softer metal than the transmission mainshaft and the pulley will generally wear out before the mainshaft. Although the splines on the mainshaft should be inspected as well as they may get some wear from the pulley rocking back and forth (which has also been a problem to some). It doesn't happen every time but it can and has happened before. So you may notice seemingly good mainshaft splines when you remove the offending pulley. But if you install a new pulley with good splines and still notice a little slop between the pulley and mainshaft, replacing the mainshaft as well may help. ((biknut of the XLFORUM https://www.xlforum.net/forum/sportster-motorcycle-forum/sportster-motorcycle-era-specific-and-model-specific/frame-mount-evo-sportster-talk-1986-2003-models/93208-bike-crapped-out-may-need-help-from-you-guys/page3)) \\ | This problem is usually caused by the lock screws and the main nut becoming loose. With even a little play, the pulley will rock on the shaft every time you open or close the throttle. This will cause wear on the splines no matter what material the pulley is made of. ((steelworker of the XLFORUM https://www.xlforum.net/forum/sportster-motorcycle-forum/sportster-motorcycle-era-specific-and-model-specific/frame-mount-evo-sportster-talk-1986-2003-models/163019-drive-pulley-number-2)) The stock pulley is made of softer metal than the transmission mainshaft gear and the pulley will generally wear out first. Although the splines on the mainshaft gear should be inspected as well as they may get some wear from the pulley rocking back and forth (which has also been a problem to some). It doesn't happen every time but it can and has happened before. So you may notice seemingly good mainshaft splines when you remove the offending pulley. But if you install a new pulley with good splines and still notice a little slop between the pulley and mainshaft, replacing the mainshaft as well may help. ((biknut of the XLFORUM https://www.xlforum.net/forum/sportster-motorcycle-forum/sportster-motorcycle-era-specific-and-model-specific/frame-mount-evo-sportster-talk-1986-2003-models/93208-bike-crapped-out-may-need-help-from-you-guys/page3)) \\ |
| | * Pulley nut wasn't properly torque'd (including Loctite) upon last installation. \\ The nut holds clamp force against the drive gear shaft. \\ It doesn't have to look loose to not have enough clamp force to hold it tight when pressure from the transmission comes onto the pulley. |
| | * Retainer plate screws loose/missing and allowing the pulley nut to loosen. |
| | * Worn splines on mainshaft (harder metal). |
| | * Worn splines on drive pulley (softer metal). |
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| **Causes Other Than Stripped Splines**: \\ | **Causes Other Than Stripped Splines**: \\ |
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| **Removal**: \\ (Caution: LEFT HAND THREADS ON SPROCKET NUT = CLOCKWISE TO REMOVE) \\ | **Removal**: \\ (Caution: 1991-UP MODELS HAVE LEFT HAND THREADS ON SPROCKET NUT = CLOCKWISE TO REMOVE) \\ |
| The 2 cap screws are right hand thread. Remove them and the metal retaining plate first. Then remove the pully nut. You'll most likely need a breaker bar also if not using an impact wrench to remove the 1-7/8" nut (it takes a lot of torque to break it loose). And you'll need to either lock the transmission from turning or lock the pully from turning to use a breaker bar/socket to remove it. \\ | The 2 cap screws are right hand thread. Remove them and the metal retaining plate first. Then remove the pully nut. You'll most likely need a breaker bar also if not using an impact wrench to remove the 1-7/8" nut (it takes a lot of torque to break it loose). And you'll need to either lock the transmission from turning or lock the pully from turning to use a breaker bar/socket to remove it. \\ |
| * [[techtalk:ref:tools131|Click Here]] to view sprocket tools in the Sportsterpedia. | * [[techtalk:ref:tools131|Click Here]] to view sprocket tools in the Sportsterpedia. |
