over revving when hot / locked up happy time / --CAUTION

1) With the cylinder studs completely removed, if my piston and rings are ok, should I be able to just slip the jug off over the piston?

2) If the piston is stuck, is my engine junk and better off being replaced, or can I knock the piston out and replace it and the rings?

1) = yes

2) = It depends on what caused the piston to stick. If the rings seized to the cylinder wall, the top end is probably toast.
If the lower bearings failed, there might have been loose metal fragments floating around in there.

I'd start with trying to get the piston out of the jug. You'll know more then.

good luck
 
Stuck Piston

Thanks, Dave.


After contemplation, a few sips of my favorite barley pop (the one that made Milwaukee famous) and a few judicious taps with a rubber mallet, the jug popped right off---cylinder firmly seized.

I found a couple of small metal shavings below the piston in the crankcase, but there were none on top when I removed the head.

I can now rotate the crank in both directions and nothing seems either loose or binding in there, so I'm counting on the bottom end being ok. The piston however, is stuck fast.

Is it prudent to try and drive the piston out with a drift at this point, or do I risk damaging the crank componenets?

I feel a little better now---looks like I need some rings and possibly a piston and cylinder, but I don't think it's a total loss at this point. I've added a wrinkle or two to the old grey matter to boot.

BTW, answer to question 4, below, the flywhell comes out of the magneto by tugging with slip joint pliers---there is a half moon key in the shaft.
 
After contemplation, a few sips of my favorite barley pop (the one that made Milwaukee famous)
Schlitz?? i have become reaquainted, as of late. :D

Is it prudent to try and drive the piston out with a drift at this point,
what's a drift?

or do I risk damaging the crank componenets?

not sure on this one???

If you can get the piston to move down far enough to get the wrist pin out, you can remove the jug & piston.... and really wail on it!!:devilish:


hopefully, one of the real mechanics, here, will have some advice for you.
 
Have you checked to see if the chain is bound up under the sprocket cover? Sounds more like that to me than a piston or crank issue.
 
Have you checked to see if the chain is bound up under the sprocket cover? Sounds more like that to me than a piston or crank issue.

If that was the problem, he wouldn't be able to pedal with the clutch disengaged.

I'm thinking something is jammed in the gears or magneto?

Usually a piston seizure has some warning signs before they go.
 
I can now rotate the crank in both directions and nothing seems either loose or binding in there, so I'm counting on the bottom end being ok. The piston however, is stuck fast.

Is it prudent to try and drive the piston out with a drift at this point, or do I risk damaging the crank componenets?

sounds seized to me......?
 
What is a drift

Dave, a drift is a fancy name for a block of wood, or a chunk of brass or some other material that is softer than the material you are getting ready to smack on with a hammer. It keeps the part from getting tool marks in it.

Hough, I've got the chain out and the motor off and all opened up---definitely a stuck piston.

Arcee, now that I have the "jug" loose from the crankcase, I can work the crank back and forth with no problem.


And, yep---proud to be a Schlitz man.
 
Okay, seized up.

Lift the jug at high as you can and hold it up with blocks of wood between the edge of the cylinder and the case so you can tap the piston down with a hammer and a piece of wood, as it moves, add more wood as needed. You don't want to pound the piston into the case, flywheels etc. You could also clamp the cylinder in a vise and support the case as it drops down with the pounding. The idea is to only pound on the piston and not damage the rod or rod bearings, crank, etc. Your cyinder and piston is going to be junk, don't worry about damaging them now. Once the piston pin is visable, remove the clip on one side (or both if you wish) and drive out the wrist pin. You should then have a "good" bottom end to work with. Flush the bottom end out with something to get any metal junk out of there before you replace the piston/cylinder assembly. You can use gas mix or brake clean to flush it. Be sure to oil the bearings good after that and before re-assembly. Any loose metal down there will damage the new parts, get it all out if even if you see none. Check your rod good too, it will wiggle side to side some but should NOT have any up and down play when you hold the crank and pull up and down on the rod If there is up and down play, the bottom end has damage too. Likely, you will just need a new top end and some gaskets. Check for air leaks at your carb, manifold and possibly the case gasket and crank seals, you could have had a leak and it was too lean causing the siezure. Is the clip set too high on the needle? Has the main jet been resized too small? are you at or near sea level? Maybe you just had a junk top end? Just pointing out that if your too lean, this could happen again after you replace the bad parts.
 
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