ROCKER BOX: Stripped Internal Threads

Discussion in 'Engine, Fuel and Exhaust' started by Mongo44, Mar 25, 2013.

  1. Mongo44

    Mongo44 Member

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    Hey y'all! Been awhile since I've posted anything here as my bike has been out of commission for awhile, but thankfully, she's back on the road. Well, she was until I messed things up!! :p

    Okay, my bike is a 1995 FLSTN (Evo 80")...

    Several nights ago, I decided to inspect my tappet screen. I have an Oil Pressure gauge that mounts to the back right rear Rocker Box bolt. I removed this to allow for easier removal of the Tappet access bolt as the cable running to the gauge would twist up too much as I turned the bolt.

    Anyway, in the process of re-installing the RB bolt, I accidentally over-torqued it and stripped the inner threads.

    After slapping myself on the back of the neck and head a few times, I accepted my mistake and set about finding a solution. What I will probably do is get a "Time Sert" threaded insert and go from there.

    However, I have a question or two. Last night, I inserted a "depth gauge" to see how deep the hole is. It is, from the RB surface to the bottom of the hole, about 1/4" deeper than the length of the threaded part of the bolt. When the gauge is installed along with the accompanying washer, it takes up maybe another 1/4" of the bolt length. So, in essence, I believe there to be around a 1/2" of non-stripped threading in the hole.

    My first question is, Does that threaded hole (in the bottom RB plate) have a bottom, or is my depth gauge going completely through it and reaching something else? I was thinking about getting a longer bolt as a temporary fix, but don't want it protruding into a space where it might get sheered-off or cause damage to another internal (moving) part.

    My second question is, Would this provide ample grip to hold the RB in place at the recommended torque value (10-13 ft-lbs)?

    Any advice is greatly appreciated! Thanks!
     
  2. lakeforktx

    lakeforktx Active Member

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    Last edited by a moderator: Mar 25, 2013
  3. Mongo44

    Mongo44 Member

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    Youuuuuuuu!!! :D Don't I know you from somewhere? Haha!!
     
  4. Mongo44

    Mongo44 Member

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    Can't seem to get any answers to this one!!
     
  5. HDDon

    HDDon Experienced Member Contributor Retired Moderators

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    First I'm using a '94 manual. The upper rocker arm cover is bolted to the lower rocker arm cover. The lower cover is aprox. 7/8" thick and may or may not be threaded through. You will need a minimum of 1/4" of thread left in the lower cover to be able to torque the cover bolt. I would put a helicoil in the lower cover and be done with it.
     
  6. Mongo44

    Mongo44 Member

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    Hey Don! Thanks for the information. I've got the '95 H-D manual and there's nothing I can find that helps me determine whether the hole goes through or not.

    I was going to use a Time Sert when the time comes. The HeliCoil has that little tab on it (to assist with installation) that you're supposed to break off when done. Either way, I think that's what's going to end up happening.

    I am just looking for a temporary fix so I can enjoy some light riding while I wait for all the parts, etc.
     
  7. HDDon

    HDDon Experienced Member Contributor Retired Moderators

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    Mongo if you take the lower cover to a small machine shop I would think they would put a timesert/helicoil or some other insert for $20 to $30. This way you don't have to buy a kit.
     
  8. Mongo44

    Mongo44 Member

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    Not a bad idea!
     
  9. BUBBIE

    BUBBIE Well-Known Member

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    My thinking is I would Make a stainless stud to fit in to bottom out... Using the 1/4 in" or more of good thread you said was left...

    After getting it all made try it out for proper length... Try it, NOT overtightening it at all, so you don't pull what threads are there. When you get it right, THEN Red Locktight it into the box... The Red will hold so DON'T overtighten it into the hole...SNUG is good enough...

    IF you can live with that it may serve you a long time. Let it sit over night after red is used so it will set up good. I don't remember how much room you have to work with but left a little long, above the new nut, a chrome acron nut will top it off nicely...:s

    signed....BUBBIE
     
  10. Mongo44

    Mongo44 Member

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    Well there's an idea I hadn't thought of!! Good one, Bubbie!

    Trying to figure something out, though...

    First, the Rocker Cover (top plate) is held on by four bolts to the bottom plate. One of these four is now stripped out (the hole, not the bolt). What I am trying to ascertain is this: If I took the bottom plate off, could I look through the mounting bolt hole, or is it only threaded partially through the plate.

    The reason I ask is that I don't want to screw something further down into the hole and have it obstruct moving parts beneath the bottom plate. Does anyone know the answer to this question? I know my depth gauge is bottoming-out, but WHAT is it bottoming-out on - the bottom of the hole, or something in the head?