Engine Trouble Piston stuck in Cylinder; can I cut cylinder?

Discussion in '2-Stroke Engines' started by rjriggs, Aug 15, 2016.

  1. rjriggs

    rjriggs Member

    I can't get the piston out of the cylinder, and the piston is too far up in the cylinder for me to reach the wrist pin. I would prefer not to destroy the connecting arm because it's still good, and I would prefer NOT to split the case, which seems like it would take a LOT of time and patience. Is there some way to possibly cut open the cylinder? It's ruined anyway, as is the piston. Any ideas on how to do this if I can't get the piston out of the cylinder?

    rr
     

  2. MotorBicycleRacing

    MotorBicycleRacing Well-Known Member

    Use a piece of wood to pound your piston out of your cylinder.
     
  3. crassius

    crassius Well-Known Member

    also, taking all 4 head studs out may allow you to turn the cylinder a bit if a ring is stuck in port - some penetrating oil in there may help too
     
  4. butre

    butre Well-Known Member

    if brute force doesn't cut it I've had to cut a cylinder off an air cooled vw motor before. I do have a pretty nasty scar from the job, so take all the precautions you can. you ever see your own bones before? an angle grinder to a foot wearing flip flops can make that happen right quick
     
    Last edited: Aug 15, 2016
  5. rjriggs

    rjriggs Member

    Another question: if I cut the cylinder apart with a grinder...would I be better off splitting the engine apart to make sure no debris gets in the crankcase? If so, I may as well go the short route and just split the engine apart, no grinder necessary.
     
  6. crassius

    crassius Well-Known Member

    I wouldn't cut it because of fine debris that may never get completely cleaned out of bearing cages and big end rollers. I'd just get another motor rather than have it lock up again in a week.
     
  7. MotorBicycleRacing

    MotorBicycleRacing Well-Known Member

    How is this going to help you?
    If you split the engine the piston will still be stuck in the cylinder with no way to detach it from the crank.
     
  8. rjriggs

    rjriggs Member

    If I split the engine, I can remove the crankarm from the crank and cut the cylinder open outside of the engine, where I don't have to worry about about debris getting in the crankcase. It would also be a lot easier to cut it that way. I'm almost scared to ask: is it really that difficult to split the engine? There's a photo guide on this website that makes it seem relatively simple...and to someone with good mechanical skills, it probably is. This is the first engine I've ever worked on in my life. Of course, I bought my HT kit to learn a bit about working on motors. I just didn't expect my education to be completed so quickly.

    So -- if I can't buy another motor, should I split the engine, or try to cut the cylinder while it's still attached to the motor by the stuck piston? If I cut the cylinder while it's still attached, what's the risk of getting potentially harmful debris in the crankcase? (Pretty high, I'd imagine.) Or is it possible to remove the crankarm from the crank without splitting the engine? (I wouldn't think so.)

    By the way, thanks for the responses to my question. I really appreciate it!
     
  9. butre

    butre Well-Known Member

    if you're stuck at bdc you might be able to cram some paper towels in the case to prevent metal getting in there. otherwise just go ahead and cut and when you're done flush the case with gas a few times.

    the difficulty in splitting the case isn't so much in the process, but rather that they come with combo head screws and require more torque to undo than to strip.
    an impact screwdriver usually does the trick though
     
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