Has anyone had this happen? HS 49 rocker arm shaft damage

Discussion in '4-Stroke Engines' started by itskeith, Aug 24, 2013.

  1. itskeith

    itskeith New Member

    roc01.jpg roc02.jpg roc03.jpg

    Hi Everyone, so there I was, minding my own business and after riding over 5,000 miles on this engine, when I noticed a drip of oil on the garage floor. I thought it was just a rocker assembly cover leak so I kept riding. Well, 100 miles later and I decided to fix it and upon closer examination, discovered that the rocker arm shaft had "wandered" and had actually worn a small hole through the cover. Apparently it had wandered both directions because there were rub marks on both sides of the cover.

    I can fix the cover with a small amount of brazing but,

    I can see no built in way of preventing the shaft from moving. Anybody else had this happen? Anyone have a fix for the shaft?

    Thanks in advance,


  2. darwin

    darwin Well-Known Member

    See how the indentations are offset on the cover? Someone installed it wrong by 180deg.
  3. MotorBicycleRacing

    MotorBicycleRacing Well-Known Member

    His valve cover is installed correctly.
  4. darwin

    darwin Well-Known Member

    Notice where the rocker pin wore on the cover, now turn the cover 180deg. Pin was meant to float side to side in those indentations. When reinstalling the cover I had to do a twice over to get it right. Anyway that's my theory.
  5. MotorBicycleRacing

    MotorBicycleRacing Well-Known Member

    Your theory is wrong.
    The valve cover has 2 pins that align it to the head.
    He has the cover on right.
    Also that flared piece is where the oil comes up the tube from the sump.
    There is also a notch on the cover where the spark plug goes.

    I will look at my motors tomorrow to see how that pin is retained.
  6. itskeith

    itskeith New Member

    Darwin, good observation but I just tried to test your theory and found that the cover would only fit, one way. The big indentation aligns with the the pipe looking thing (breather?) that comes out vertically on the right side.
  7. MotorBicycleRacing

    MotorBicycleRacing Well-Known Member

    The oil comes up that "pipe" to lubricate the top end.
  8. itskeith

    itskeith New Member

    Ooh, the oil pipe, an engine can't live without the life blood.
  9. darwin

    darwin Well-Known Member

    MBR your right after looking at it again. Been awhile since I had a HS and I remember doing the valves that the cover I almost put on backwards or something. Thought that might be the problem. Wonder if the Honda is exactly the same? Been couple of years since I've adjusted the valves on one.
  10. Bgard

    Bgard New Member

    Good eye guys that looks like the problem. I would think that the rocker pin would be secured some how.
  11. MotorBicycleRacing

    MotorBicycleRacing Well-Known Member

    Yes the Honda is the same except the Honda parts look better.
  12. Quenton Guenther

    Quenton Guenther Motored Bikes Sponsor

    Looks like a new issue to me. I had to take the cover off a new motor to see how the pin is secured. I will attach a picture to help explain how the pin is held in "check". At the rear of the pin [rear side of motor, nearest carburetor], the boss has a flat spot to stop the pin from moving, nothing stops the pin from moving forward, however it appears the pin only wants to move towards the rear when the motor is running.
    I also checked a Honda GXH50 test motor in the shop and it is made the same way.

    Looks like the barrier allowed the pin to move in both directions on your motor.

    I would think there are several easy options to fix the issue. Reconstruct the barrier on the head with anything from JB Weld to strong epoxy mixtures. A simple application of "sleeve retainer", Loctite green or any other high strength liquid where the pin sits in the guide hole.

    Motor can be "short blocked" if under warranty [EZM motors carry a 1 year warranty].

    Have fun,

    Attached Files:

  13. itskeith

    itskeith New Member

    Hi Guenther, thanks for spending the time to help me with this. I have had 5,000 miles of trouble free service with this engine and it still runs the same as ever. I could not see that there was ever a "block" present as shown in your photo. Nevertheless, I used JB Weld to build up the stop block according to your suggestion. Thanks again
  14. Quenton Guenther

    Quenton Guenther Motored Bikes Sponsor

    If you have any problems with the shaft in the future, we can make a small collar [locate between pin guides] to hold the pin in place. Just let us know if you need any help.

    Have fun,
  15. itskeith

    itskeith New Member

    You're the best, thanks.
  16. HeadSmess

    HeadSmess Well-Known Member

    neat. easy fix but. maybe a bad batch of castings. more likely management saying remove excess lumps, save us money!

    ive had those rocker bearing thingies break off completely ( idont know how...) but never seen a wanderer like that!

    5000 was pretty good innings too