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techtalk:ih:engmech01a [2018/05/16 21:19]
hippysmack [Sprocket Cover Dowel Hole (Case) Repair]
techtalk:ih:engmech01a [2023/12/31 19:34] (current)
hippysmack
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 ====== IH: Engine Mechanicals - Sub-01A ====== ====== IH: Engine Mechanicals - Sub-01A ======
 ====== Sprocket Cover Dowel Hole (Case) Repair ​ ====== ====== Sprocket Cover Dowel Hole (Case) Repair ​ ======
-Article by Hopper of the XLFORUM ((http://​xlforum.net/​forums/showthread.php?​t=395586)) +Article by Hopper of the XLFORUM ((https://www.xlforum.net/​forum/sportster-motorcycle-forum/​sportster-motorcycle-era-specific-and-model-specific/​ironhead-sportster-motorcycle-talk-1957-1985/​63858-special-tools?​t=395586)) 
-  * This is a bit of an obscure one but a real pain to fix, requiring several special tools. This was also done with the cases assembled. If had split the cases I could have put them on my mate's milling machine and precision machined them. But because I was too lazy to split the cases and disturb that nice tight, factory original bottom end, I did it the hard way. ((Hopper of the XLFORUM ​http://​xlforum.net/​forums/showthread.php?t=395586))+  * This is a bit of an obscure one but a real pain to fix, requiring several special tools. This was also done with the cases assembled. If had split the cases I could have put them on my mate's milling machine and precision machined them. But because I was too lazy to split the cases and disturb that nice tight, factory original bottom end, I did it the hard way. ((Hopper of the XLFORUM ​https://www.xlforum.net/​forum/sportster-motorcycle-forum/​sportster-motorcycle-era-specific-and-model-specific/​ironhead-sportster-motorcycle-talk-1957-1985/​63858-special-tools/​page2?​t=395586https://​www.xlforum.net/​forum/​sportster-motorcycle-forum/​sportster-motorcycle-era-specific-and-model-specific/​ironhead-sportster-motorcycle-talk-1957-1985/​172350-77-breather-please-view-pics/​page2?t=1845601&​page=2))
     * When it came back from the aircraft welder it looked like the pics below.     * When it came back from the aircraft welder it looked like the pics below.
     * Amazingly, there was no big blob of weld but two tiny little rings, still with the (rough) hole in the middle. His TIG welder can weld aluminum .010" thick.     * Amazingly, there was no big blob of weld but two tiny little rings, still with the (rough) hole in the middle. His TIG welder can weld aluminum .010" thick.
     * The gearbox shafts and bearings were left in place during welding to help stop distortion of the cases. ​     * The gearbox shafts and bearings were left in place during welding to help stop distortion of the cases. ​
     * He pre-heated the cases gently with a torch and then he would put a ring of weld on, let it cool off, repeat, repeat repeat etc.     * He pre-heated the cases gently with a torch and then he would put a ring of weld on, let it cool off, repeat, repeat repeat etc.
-    * Notice how he welded around the screw next to the top hole but did not go over it. And the 1/4" threaded hole in the middle was still useable. ((photos by Hopper of the XLFORUM ​http://​xlforum.net/​forums/showthread.php?t=395586))+    * Notice how he welded around the screw next to the top hole but did not go over it. And the 1/4" threaded hole in the middle was still useable. ((photos by Hopper of the XLFORUM ​https://www.xlforum.net/​forum/sportster-motorcycle-forum/​sportster-motorcycle-era-specific-and-model-specific/​ironhead-sportster-motorcycle-talk-1957-1985/​63858-special-tools/​page2?​t=395586https://​www.xlforum.net/​forum/​sportster-motorcycle-forum/​sportster-motorcycle-era-specific-and-model-specific/​ironhead-sportster-motorcycle-talk-1957-1985/​172350-77-breather-please-view-pics/​page2?t=1845601&​page=2))
  
  
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   * I also sleeved the sprocket cover down with a steel sleeve so the hole for the footpeg stud was a tight fit and would take most of the weight in future.  ​   * I also sleeved the sprocket cover down with a steel sleeve so the hole for the footpeg stud was a tight fit and would take most of the weight in future.  ​
  
-|  Drill jig made from a half-inch steel plate to guide the drill ((photos by Hopper of the XLFORUM ​http://​xlforum.net/​forums/showthread.php?t=395586))  ||+|  Drill jig made from a half-inch steel plate to guide the drill ((photos by Hopper of the XLFORUM ​https://www.xlforum.net/​forum/sportster-motorcycle-forum/​sportster-motorcycle-era-specific-and-model-specific/​ironhead-sportster-motorcycle-talk-1957-1985/​63858-special-tools/​page2?​t=395586https://​www.xlforum.net/​forum/​sportster-motorcycle-forum/​sportster-motorcycle-era-specific-and-model-specific/​ironhead-sportster-motorcycle-talk-1957-1985/​172350-77-breather-please-view-pics/​page2?t=1845601&​page=2))  ||
 |{{:​techtalk:​ih:​engmech:​sprocket_cover_dowel_hole_repair_3_by_hopper.jpg?​direct&​400|}}|{{:​techtalk:​ih:​engmech:​sprocket_cover_dowel_hole_repair_4_by_hopper.jpg?​direct&​400|}}| |{{:​techtalk:​ih:​engmech:​sprocket_cover_dowel_hole_repair_3_by_hopper.jpg?​direct&​400|}}|{{:​techtalk:​ih:​engmech:​sprocket_cover_dowel_hole_repair_4_by_hopper.jpg?​direct&​400|}}|
  
   * Because the top hole has a 1/4 bolt running through it, and the weld was off centre, I made a special drill/​cutter out of 7/16" silver steel. It had a 1/4 inch hole up the centre so it could fit over a threaded stud screwed in the hole. I cut two flutes on the end of it with an angle grinder so it is like a milling cutter, or flat-nosed drill. Finished it off on the pedestal grinder. I then flame hardened it with the oxy torch. Heated it cherry red then quenched in oil. Then tempered it to a light straw color and quenched again. ​   * Because the top hole has a 1/4 bolt running through it, and the weld was off centre, I made a special drill/​cutter out of 7/16" silver steel. It had a 1/4 inch hole up the centre so it could fit over a threaded stud screwed in the hole. I cut two flutes on the end of it with an angle grinder so it is like a milling cutter, or flat-nosed drill. Finished it off on the pedestal grinder. I then flame hardened it with the oxy torch. Heated it cherry red then quenched in oil. Then tempered it to a light straw color and quenched again. ​
  
-|  {{:​techtalk:​ih:​engmech:​sprocket_cover_dowel_hole_repair_5_by_hopper.jpg?​direct&​400|}} ((photo by Hopper of the XLFORUM ​http://​xlforum.net/​forums/showthread.php?t=395586))  |+|  {{:​techtalk:​ih:​engmech:​sprocket_cover_dowel_hole_repair_5_by_hopper.jpg?​direct&​400|}} ((photo by Hopper of the XLFORUM ​https://www.xlforum.net/​forum/sportster-motorcycle-forum/​sportster-motorcycle-era-specific-and-model-specific/​ironhead-sportster-motorcycle-talk-1957-1985/​63858-special-tools/​page2?​t=395586https://​www.xlforum.net/​forum/​sportster-motorcycle-forum/​sportster-motorcycle-era-specific-and-model-specific/​ironhead-sportster-motorcycle-talk-1957-1985/​172350-77-breather-please-view-pics/​page2?t=1845601&​page=2))  |
  
-|  Using an electric drill (and proceeding very carefully), came up looking like this. ((photos by Hopper of the XLFORUM ​http://​xlforum.net/​forums/showthread.php?t=395586))  || +  * In the final fit up, I made custom dowel pins and fitted them with a small file and some bearing blue so they are tight as tight and wont work loose again. 
 +  * I also drilled and tapped that top stud out to 5/16 for more strength and also plan to add a steel angle bracket from the top of the sprocket cover to the two bolts on the top of the gearbox near rear mounts. SOB will not move ever again!! 
 +  * I still had to strip the gearbox and replace those bearings that had been welded right next to. 
 + 
 +|  Using an electric drill (and proceeding very carefully), came up looking like this. ((photos by Hopper of the XLFORUM ​https://www.xlforum.net/​forum/sportster-motorcycle-forum/​sportster-motorcycle-era-specific-and-model-specific/​ironhead-sportster-motorcycle-talk-1957-1985/​63858-special-tools/​page2?​t=395586https://​www.xlforum.net/​forum/​sportster-motorcycle-forum/​sportster-motorcycle-era-specific-and-model-specific/​ironhead-sportster-motorcycle-talk-1957-1985/​172350-77-breather-please-view-pics/​page2?t=1845601&​page=2))  || 
 |{{:​techtalk:​ih:​engmech:​sprocket_cover_dowel_hole_repair_6_by_hopper.jpg?​direct&​400|}}|{{:​techtalk:​ih:​engmech:​sprocket_cover_dowel_hole_repair_7_by_hopper.jpg?​direct&​400|}}| |{{:​techtalk:​ih:​engmech:​sprocket_cover_dowel_hole_repair_6_by_hopper.jpg?​direct&​400|}}|{{:​techtalk:​ih:​engmech:​sprocket_cover_dowel_hole_repair_7_by_hopper.jpg?​direct&​400|}}|
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