Swinging arm bush replacement

Forums Technical Two Stroke: Help needed Swinging arm bush replacement

Viewing 4 reply threads
  • Author
    • #9939
      ‘AAA Dummy

      I’ve had the frame & swinging arm of my ETZ 251 powder coated.
      On the rebuild now, but struggling to find a way to fit the replacement rubber bushes and steel inner sleeves on the swinging arm.
      The Haynes manual suggests taking it to a dealer and the MZ manual is vague. I’ve pressed in the rubber bushes in their own, but the bore then closes up too small to insert the steel sleeve. Putting the steel & rubber parts together first leaves the rubber OD far too large to get a start into the swinging arm. I’m sure there must be a ‘real world’ DIY method that I’ve not worked out yet – can anyone help?
      Many thanks,


    • #9940
      Membership Man

      Not a job I would ever want to tackle again. However, I was reasonably succesfull using the following method. Use some rubber lubricant on the outside of the rubber bush but not on the inside unless absolutely necessary. Push the rubber bush about 1/3 to 1/2 into the fork end then push the metal bush into the free end by hand until it won’t go further. Put the whole assembly into the vice and squeeze the metal bush into the fork end. With luck it will take the rubber in with it squeezing it thinner as it goes. You may have to try this several times before you get it right. The rubber bush elongates and thins down as its pushed into place.

      Lubricating the outer part of the rubber bush helps it to slide into the fork end. Not lubricating the inner helps create enough friction to push the rubber bush into place rather than simply sliding the metal part straight through. At least that’s the theory. It worked for me in the end – but never again


    • #9941
      ‘AAA Dummy

      Hi Peter,

      Many thanks for your prompt reply. Closer reading of the works MZ manual calls for the bush in first, then references a tapered mandrel, to gradually open the bush up tp the diameter of the sleeve.mounted to it, which makes sense for those with a lathe or the will to pay for one to be made up. In the meantime I’ll persevere and give your method a go. I have a small lever press which should help.
      Fingers crossed….

    • #9943
      ‘AAA Dummy

      Well, thanks to Peter’s technique and plenty of determination the bushes are in! I refined the method a little by polishing the bore of the two swinging arm sleeves and soaking the rubber bushes in hot water before I started.
      Thanks again.

    • #9974

      getting the two bushes into the frame is one of the most difficult jobs to attempt on mz etz s still now you have managed- it good work. best George 31

Viewing 4 reply threads
  • You must be logged in to reply to this topic.