How to free a seized HT piston?

Discussion in '2-Stroke Engines' started by mbatl, May 24, 2012.

  1. mbatl

    mbatl Member

    I'm working on a HT bike for someone who doesn't know much at all about the mechanics of these engines. He ran regular gas in the HT because he ran out of 2 cycle gas away from home and of course it seized.

    I have the cylinder jug loose but the piston is stuck in it and wont budge.

    Whats the best way to free the piston so I can continue disassembling the engine? I tried PB Blaster but so far no luck.

    In this situation, the cylinder jug where the piston rings froze is trash correct?

  2. Lunardog

    Lunardog Member

    I would say thats a fair assumption. If it got to the point the rings actually siezed to the cylinder walls the jug is shot. Piston may be salvagable and thats a big maybe . The rod and crank bearings will need inspecting too. Best I could suggest is soak it for a day or two hitting it with the PB blaster spray a couple times and then try to drive the piston out with a block of wood and a hammer. Unfortunately at this point its a **** shoot what can be saved. Good luck.
  3. mbatl

    mbatl Member

    Thanks for the response. After leaving with pb blaster awhile then torching it I was able to get it out with a huge iron stake.

    Now I'm researching top end rebuild kits and researching what special tools and special techniques are required.
  4. Cavi Mike

    Cavi Mike Member

    Just pound it out. Nothing there is salvageable. It's like $50 for a brand new slug and jug. To bore and re-coat that cylinder will cost way more money than any of it is worth and then you'll have to source an over-sized piston as well...good luck with that.