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Tech Tip - Sprocket Replacement
http://www.hobie.com/forums/viewtopic.php?f=60&t=12580
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Author:  mmiller [ Fri May 22, 2009 5:24 pm ]
Post subject:  Tech Tip - Sprocket Replacement

Thank you roadrunner for the following article:

This procedure illustrates the removal and replacement of sprockets and drums.

Tools and Materials used: Phillips head screw driver (not shown); shaft removal pin (an old mast works well); hammer; 7/16" wrench; 1/8" Allen wrench; needle nose pliers (optional); needle nose vice grips (for old style cable removal); Loctite; grease.
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1. Remove chain/cable nuts on one side; peal away chain. This is probably a good time to remove and set aside your fins.
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2. Unscrew Allen screw that holds the sprocket shaft in position. This is located between the sprockets on the right side.
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3. Slide drums off (recommended) for convenience. Remember which side they go on.
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4. Tap sprocket shaft out. Tip: if shaft resists movement, it is probably corroded. Lube w/ penetrating oil and tap one way then the other to loosen it up.
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5. Clean all parts (including drums). Note notch at center if sprocket shaft where Allen screw seats. Remove any surface corrosion on shaft w/ steel wool or crocus cloth as necessary.
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6. Transfer sprocket guard and clew outhaul to new sprockets if you are replacing them. Drill pilot holes if necessary for sprocket guard screws.
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7. Mark CLEAN DRY sprocket shaft on both clean ends using permanent marker or grease pencil (better). Tip: your mark should be accurately marked with the notched side clearly indicated. Note: permanent marker is not permanent in the presence of grease -- be careful not to accidentally wipe it off until finished
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Tip: Reverse shaft if it is worn or scored to leave the fresh side facing down. This side shows wear and will be reinserted facing up.
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This side looks virtually new and will be inserted face down. Image

8. Mark chain at middle link to help locate master cog later
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9. Grease sprockets inside clean shaft using Q tip or clean stick. LIGHTLY grease the half of shaft that is going back in first.

10. Install shaft from either end noting location of slot.
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Tip: push shaft in to sprocket cavity slightly to help locate sprocket as shown:
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11. Check alignment before finishing inserting sprocket shaft; then tap in remainder of way
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12. Loctite Allen screw and seat screw. Tighten snugly, but do not over tighten so as to stress bearing surface. Pic shows approximate proper seating depth. If it's not recessed, it's not properly seated.
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13. Grease and slide drums onto drum shaft, noting correct side (drums are actually reversible but pedals, once installed are not).

14. Note master cog on sprocket is fatter than the others. Press the marked chain link into this cog. It may take some doing to get the chain fully seated, especially with a new chain and new sprocket. Work from the master cog out to either side to make sure the chain is fully seated.
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15. Reinstall chain/cables working forward from the rear chain. If you are installing the new '08 style drums and chains, here is more detail: viewtopic.php?t=8642
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16. Adjust chain/cables starting with the idler cable and working back. See this link (step #3) for additional adjustment instructions if necessary. viewtopic.php?p=29602#29602
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