Z50 rocker pin in backwards

Discussion in 'Tech Area' started by mk2davis, May 15, 2018.

  1. mk2davis

    mk2davis Member

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    This one proves to be a toughy. I just bought a Z50 that has seen better days. I'm going through the whole motor, but the thing that is stumping me at the moment is the rocker pin that has been installed backwards. Therefore, I don't have access to the female threads to pull the pins out. Because of the condition of the motor overall (it looks like water got into the oil), no amount of skillful shaking is going to work this pin out.

    I can't be the first to have this issue. Any and all help appreciated.
     
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  3. hrc200x

    hrc200x Active Member

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    can you use a longer pick with a 45 degree tip on it to reach all the way through the pin and get to the threads?
     
  4. Cleato904

    Cleato904 Member

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    Try these. If the pin has movement you could try with a strong magnet to coax it out. Have the cylinder laying on it's side while pulling down with a magnet and free gravity and try to turn the pin with the magnet.The other method I've used, is if you have access to a ultrasonic cleaner is to suspend the cylinder on its side and cycle the cleaner to clean and viberate the pin out. Hope this helps.
     
  5. dirtbkr188

    dirtbkr188 Active Member

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    You could try using an M8 x 1.25 tap to cut into the end of the rocker pin enough for you to be able to pull it out. The tapered end might thread in just enough to get a good bite.
     
  6. racerx

    racerx Administrator
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    Try heating the head casting to ~400F, using a propane torch...carefully...concentrating the heat on the aluminum surrounding the rocker pin. Work as quickly as possible, to keep the rocker arm & pin from heating-up and expanding, too. Wrapping the rocker arm with a wet rag might help; water can absorb an incredible amount of heat energy and aluminum heats-up very quickly. A parts-retrieval tool (the telescoping variety) with a rare earth magnet, is about as much damage-free pulling power as you're going to get from just the end.

    A stiff wire, folded into a barb, might be better.
     
  7. mk2davis

    mk2davis Member

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    This sucker is in there pretty good. A magnet won't cut it. The pin turns, just won't come out, so a tap won't work. This was my first thought. Not sure how well it would have worked, as I think the pins are hardened? I don't have a US cleaner, but I have a tumbler somewhere...

    I just might give the torch a try. Al should expand a lot more than steel, similar to applying a heat gun to a wheel and freezing a bearing. And that's interference fit. I'll report more tomorrow.
     
  8. racerx

    racerx Administrator
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    hrc200x had a good idea and that's what I tried to expand upon (poorly as it turned out) in #5. Actually, you only need to get the pin a little bit past the outside surface of the head casting to be able to grab it with pliers. A 90-degree pick could do the job but, it'd have to be cut down just short enough to fit through the pin bore. If you don't mind sacrificing a small pick, the mod would only take a few seconds at the grinder.

    Have you tried using a bolt that's slightly smaller than the non-threaded ID of the pin? I've extracted reversed pins with nothing more than this. Insert the threaded end into the pin, press it at an angle to side-load the bolt threads, then use it as an extractor...pull it slowly. It may take the pin with it; seeing as you said the pin can be easily spun inside the head, it may not require much force. FYI, the 110mm long M6 cam cover bolt is long enough to reach through the pin and into the threaded end. I know, it won't engage those M8 threads. That said, with some lateral loading via the long bolt, the threads will grab...hopefully just enough to get the pin moving. I'd try this before breaking out the propane heat.
     
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  9. kirrbby

    kirrbby Well-Known Member

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    Rest assured that you WILL be able to get it out. But you HAVE to make sure not to damage the hole that it goes into...the hole in the head casting. Whatever methods you try, be careful not to monkey up the head casting.
     
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  10. kirrbby

    kirrbby Well-Known Member

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    Also, check to make sure that the rocker isn't the problem. It could be kinda siezed onto the pin.
    ...Figure out what's fighting you.
     
  11. mk2davis

    mk2davis Member

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    It seems that the pin is spinning freely inside the rocker, and I've managed to get the pin to come out a little bit, but not far enough to get another tool on it. I'm going to grind an allen wrench to shape because it is hardened. Hopefully that will do the trick. After that, it's camshaft time. It's frozen in place and won't rotate, but hopefully soaking it in penetrating oil will do the trick.
     
  12. mk2davis

    mk2davis Member

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    I forgot to mention that I have tried laterally loading the threads with an M6 to no avail. I might try pushing the pin back in, and polishing the exposed hole. I think its corrosion that is shrinking the hole, and currently any progress pulling the pin out is allowing the corrosion to accumulate. Then, as always, ample amounts of lube.
     
  13. racerx

    racerx Administrator
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    I dunno...corrosion seems highly unlikely, unless the head has been off the engine for a long time. While assembled, those pins are well-oiled, with outside air sealed-out.

    Your modded Allen wrench tool should work. If you have Vise grips and a rubber, or plastic, mallet you could create a makeshift slide hammer. Once you get the inside edge (the end with the internal threads) free of the head casting, removal should be pretty easy the rest of the way.
     
  14. fatcaaat

    fatcaaat Well-Known Member

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    Well, one sure fire way to get it out is to take a die grinder with a cutter and slice right through the center of the rocker and pin...you'll get it out that way for sure.

    However i had this issue myself once and recall using a tap. i threaded it in and kept threading twisting and pulling at the same time and it was able to be walked out. is there a little hole in the rocker that exposes the pin? Can you put pressure on there to keep it from spinning? while you put a tap in it? I guess you could also Do they make an expander tool that would allow you to slip it in and tighten up then pull? Like the rubber mounting you might put in the end of handlbar for weights/dampening?
     
  15. OLD CT

    OLD CT Well-Known Member

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    Find a old drill bit or a bolt that will slide in the pin. Put a small dab of gorilla glue or epoxy on the bolt and slide it in a half inch and and let it dry overnight. That should work as long as you don't use way too much.
     
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