This is a common problem with all 57-03 Sportsters. It doesn't matter if you’re working on an Ironhead or Evo, drain plug or timing inspection plug. The problems and solutions are all the same.
Case in Point:
See this undercut unthreaded area? All oil plugs are made like this in Milwaukee. 6) |
Timing inspection hole location on a pre-91 engine case (centered between the two cylinders on the left crankcase) 12) | Timing inspection hole location on a 91-03 engine case (centered between the two cylinders on the right crankcase) 13) |
* Once removed, check the threads on the plug and in the case for damage before trying to re-install the plug. Any damage(no matter how small) can be compounded each time you re-install the plug. This will also give you a clue as to what you may encounter the next time you remove it (for instance, if it is necessary to give it a 'soft hug' when re-installing instead of how you are used to handling it) so as to preserve the threads for as long as possible. These are straight (not tapered) threads on the plug and in the case. There is no need for the plug to have tapered threads with it having a head on the end. Inspect them closely and, in the case of warped or damaged threads, first try to repair or 'chase' the existing threads if you have any left. This will keep you from having to drill into the case if it isn't necessary.
See Leaking Oil From the Drain / Timing Plug in the Sportsterpedia.
In an emergency or as patch until you can have a permanent solution done, here are some possible ideas in the Sportsterpedia to keep you riding (Drain Plug Sealing and Temporary Fixes). A temporary repair is just that. It may blow out at any time. It's best to have a spare with you in case the current temporary fix blows out, especially if your away from home. 14)
See also the warped or damaged thread repair section of the Sportsterpedia.
5/8“x18 NF 'bottoming' hand tap for the case threads (which is flat on the end with a short a taper) | 5/8”x18 NF die for the plug |
Tape the length of threads to repair on the tap using the plug as a guide | The pick is to guide and maneuver the panty hose |
Start the tap by hand. Be sure you catch a few good threads as you turn in order to retain the original straightness and center | Run the tap in all the way to the taped area and then back it out |
With the threads repaired, they now need to be cleaned up | Run the tap back in by hand. The remaining chips will cling to it |
Once satisfied with cleanliness, cut a new piece of panty hose, poke it thru the center of the hole, pack it in as before, grab it with the hook and turn it out counterclockwise |
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The factory timing hole plug can be up to app. 1/2 the length of the threads in the case on Evo engines and the entire length minus a couple threads on IHs. If you have stripped threads in the front half of the case, chances are the threads in the rear half of the case hole are still good.
The head may be larger than the original but it can be ground to fit with a bench grinder. 30) | ||
Measure the heads on the old and new plug, grind the new one if needed. 31) | ||
Prepping the Hole
This is how this task is usually accomplished and it will sling chips as you drill. See Debris Control above.
Choosing the Right Reamer
Aftermarket drain plug on a '71 XLCH 38) |
See also 91-03 Timing Inspection Hole and Plug Pics and App. Dims to help in deciding what size inserts you need.