Engine Trouble Second hand parts engine with shockingly bad damage!

Discussion in '2-Stroke Engines' started by SEGACDX, Apr 18, 2016.


    SEGACDX Member

    I just want to start this off by saying, Wow did this guy f**k this engine up!

    I'd expected some minor damage but what I ended up finding inside was a complete engine failure.

    The piston was so pitted up I had never seen anything like it before, the head was much the same with large pits all over the inside.

    More of the studs and bolts where stripped and bent to hell and back.

    After prying the thing open I found the problem a completely destroyed crank bearing.

    I'd never seen anything like this before and the most shocking part was it was only 4 months old!

    Lucky I was able to use the parts I needed and there are still a lot of good parts I can use from it but how can anyone f**k something so simple up this badly?

    There where even cracks on the carburetor cap somehow, missing the idle screw and the clutch had no retainer screw.

    The Clutch side had a big ass peace missing I'm guessing it could be from the woodruff key was destroyed, you could tell he did not have the right tools because you guessed it the screw for the small gear was in super bad shape.

    I had gotten a box of very good parts in great shape beforehand for about 15$ with most of an engine but missing a few oddball things, at lest this mostly complete kit I got for 45$ which really I should have paid much less for because for the shape of it.

    I can make another complete engine with what I have since they both use ZAE 50 crank and piston while my older currently in use engine uses the FM80 Crank and I just happened to get two brand new pistons with my oddball parts box.

    On a side note it was very odd I got a center-fire head with my oddball box I wonder if it was the original head since everything in there is almost brand new? Well I have a slant head for it now even if it's been painted black and have some pits I need to take care of before I use it.

    I'll take some pictures just to show how bad this guy messed up. He told me he was running 40-1 Ratio so that may have done it I run 32-1 and never had any problems but that's my experience but I've always tried to keep it in tip top shape.

    There is one thing I can't seem to get off the crank and the crank case and that's the bearing inner race and outer race would anyone happen to know how I could get those off? I've rebuild these engines before so I've dealt with installing bearings but not removing broken ones.

    Anyways had anyone ever got a second hand engine this bad or worse? Maybe even destroyed a few themselves? I'd love to hear it and maybe even see some pictures of your messed up engines!
    Last edited: Apr 18, 2016

  2. crassius

    crassius Well-Known Member

    pretty common - I sell a lot of motors when rod bearings go at one end or other - often chunks will break right thru cylinder walls at the ports
  3. sbest

    sbest Active Member

    Yup, I've had lots worse.
    The pits in the head and piston, are they bearing bits? Broken ring pieces or detonation?
    Removing the crank, file any burrs off the crank bearing shaft so it can slide out of the bearing.
    Use some heat (propane torch) on outer diameters to expand them.
    BE GENTLE. The big hammer destroys a lot of stuff.

    I am interested in picts of the head. Centerfire is theoretically better but there are some horrible chanber shapes out there.


    SEGACDX Member

    The pits are a bit better since I had polished them with the wire wheel right after I pulled it apart to try and buff them out a bit.

    I have taken some pictures that can be viewed in high resolution by clicking to them to zoom to full size.

    The album and be found here: http://imgur.com/a/BZKJz

  5. butre

    butre Well-Known Member

    something was inside the engine, like a pebble or a piece of steel or something

    SEGACDX Member

    Maybe, I've never seen anything like it but I plan to smooth out the head with a Dremel an angled bit and and paper since it's still good and use the old piston as a practice piece for porting.
  7. 45u

    45u Active Member

    The motor I bought had so much grit and trash in it from the factory as well as the rod bearing was sticking with trash. I did not even fire it up till I took it all apart and cleaned it out. I think this is why the recommend running so much oil when breaking in.