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Stuck Piston/Crankshaft
Posted: Mon Nov 14, 2011 11:26 pm
by tatchity
Hey all, again thanks so much for your help for the new guy. Much appreciated!
In a previous post, I discussed putting new rings on my Taz 44BBK. Thanks to your help, I was successful in putting those on! I have run into a secondary problem however, one that Google and this forum suggest may be a pain!
During installation of previously mentioned piston rings, I broke a set on my first attempt. I am guessing (I did not see this happen) that a piece of ring went into the crankcase. (As a noob, I did not stuff a rag into the crankcase hole. I will do this for certain in the future!!!!)
Now, I can only turn the crank over (via moving the flywheel) about 300 degrees before it locks HARD. A full revolution is almost impossible, and I didn't want break anything so I didn't push it.
Is there a way to diagnose/solve the problem without pulling the whole thing apart? I don't have the expertise/or tools at moment to tear the whole lower end apart, so I was hoping to avoid that

Would it be as easy as taking the engine off the mount and flipping it upside down and seeing what falls out?
Much thanks as always, any help would be greatly appreciated.
Tom
Prairie Village, KS
Stuck Piston/Crankshaft
Posted: Mon Nov 14, 2011 11:44 pm
by Carnie
It could be as easy as taking the engine off and flipping it over and givin it a good shake but what I did was give it a good blow out with an air compressor, then sprayed a little carb cleaner and 2t oil in there then sprayed it out again. Then when I twisted the fan engine and wiped off the crank as it turned of any access fine debris. This worked great and I got full action after and only took 10 min. Longest part was pressurizing my compressor.
Re: Stuck Piston/Crankshaft
Posted: Tue Nov 15, 2011 3:55 pm
by eliteguy50
Carnie wrote:It could be as easy as taking the engine off and flipping it over and givin it a good shake but what I did was give it a good blow out with an air compressor, then sprayed a little carb cleaner and 2t oil in there then sprayed it out again. Then when I twisted the fan engine and wiped off the crank as it turned of any access fine debris. This worked great and I got full action after and only took 10 min. Longest part was pressurizing my compressor.
That is what I do except I use gasoline instead of carb cleaner for the flush. The gas will clean out some of the oil too so after the final flush, I rinse it with a heavy premix.
Always use compressed air, never a vacuum.
Re: Stuck Piston/Crankshaft
Posted: Tue Nov 15, 2011 8:32 pm
by z50r-ghost
I've heard of many doing the slosh-method then compressed air to get a piece of ring or a circlip out of a case... BUT the only tried and true method, that gives piece of mind to me, is pulling those cases apart, and making sure a tiny piece of metal is not lodged in your bearing races... Just an idea...
j
Re: Stuck Piston/Crankshaft
Posted: Tue Nov 15, 2011 8:44 pm
by wentwest
If it turns free except for the last 60 degrees, it sounds like there's a piece of something lying in the bottom of the crankcase that jams the big end of the connecting rod as it comes to the bottom. I have a magnet on a rod that looks like a radio antenna and I have fished out things like this by just blindly poking around down there. Poke, poke, poke, then look at the magnet end and see what's there. You might get lucky. I found all the balls from a disintegrated cam bearing that way in a 4 cycle Honda scooter engine.
Stuck Piston/Crankshaft
Posted: Wed Nov 16, 2011 12:27 am
by Carnie
Before you go and split the case though, at least try the other method and see what your results are. Mine were better than what I asked for and if it isn't satisfactory, split the case but that's a lot of time and leaves more room for error, plus you have to acquire the fan engine tool to get to the bolts behind.
Stuck Piston/Crankshaft
Posted: Wed Nov 16, 2011 12:28 am
by Carnie
Let us know if you have any luck though!!
Re: Stuck Piston/Crankshaft
Posted: Sat Nov 26, 2011 7:27 pm
by tatchity
Hey all,
Just wanted to give you a heads up that some patience, a flashlight, and a magnetic "reacher" guy have done the trick. I pulled a bunch of little shredded piston ring pieces out of my crank case, and it turns true now. I prolly will hit it with some compressed air before I put the whole she-bang back together, but it seems like we are good to go.
Thanks for your assistance!
Tom
Stuck Piston/Crankshaft
Posted: Sat Nov 26, 2011 8:02 pm
by Carnie
Good deal. Make sure you get all those little bits and fine debris out. Save you from similar problems in the future.
Re: Stuck Piston/Crankshaft
Posted: Mon Nov 28, 2011 5:56 pm
by Wheelman-111
Greetings:
Please, I'm already enough of an insomniac. Now I can't sleep at all until you tell me you won't reassemble this engine as is.
Y'see, there's that other little segment of piston ring stuck to the back of the crankcase. You know, the one your magnet couldn't reach? The thick 2-smoke oil residue that lives in the cases has it glued to the back wall - for now. Once the engine starts, vibrates, warms up and blasts the oil slush with machine-gun waves of fuel vapor, it'll come UNstuck. Where it goes and how much havoc it wreaks is anyone's guess.
Pull the cases apart and do it right, or more than likely you'll be doing it over. Hope I'm mistaken.