MOPED ARMY

Add some heat into the mix after you drain the pb fluid. You could also just plan on replacing your crank. I am not too familiar with the 505 engines but you should be able to find a new one. If you can find a new crank you could just cut the old one off at the con rod and the will allow you to remove the jug from the rest of the engine. Or even just split the cases and remove the crank without cutting.

Just my first thoughts if the jug is un willing to come loose from the piston. Heat before destroying though.

normally id just take a blunt object that fits in the cylinder and use a large sledge hammer to tap out the piston using the weight of the hammer to shock it little by little, but the sachs cylinder is different. maybe you can try this but stick something in the spark plug hole and tap it out. gl

I fixed a guys moped that had a jug once. Can’t remember what it was but the piston was stuck.

After soaking, like you are doing, I looked in and saw the piston was below TDC but not too far. So, I stuck a wood dowel rod in the spark plug hole and beat it with a hammer until the piston broke free.

I also used electrolysis to remove rust from the tank. 1st time trying that. Made a nasty mess but was fun.

He had his moped back in a week and used it for moving his ass around the drag strip on race days. Guess all that banging didn’t mess it up too bad.

I would never do that for myself or to sell something but it’s what he asked me to do. Just get it to run. Proved a point about how resilient a stock moped can be.

Sorry for the long story. I maaaaay be drunk.

I wonder how much air or water pressure applied through the spark plug hole might move that piston? (Water is safer if you can figure out a way to apply high pressure.)

Mark Kinsler

ok the grease gun comment got me thinking....you could buy a loaf of bread and shove a ton down in there till its full and just keep pounding with a dowel and filling till the crank starts moving....idk worth a shot last resort maybe

I thought I replied

things I've had success with:

1) put a lot of penetrating oil I. spray in the plug hole, through the intake, through the exhaust, and under the piston (pull it out as far as you can to spray from the bottom too

2) twist it. with the jug pulled off the studs, sometimes twisting gets more torque than yanking it directly off. don't go so hard you bend the crank, but that's not likely unless you're hulking it like a maniac

3) if all above fails, put the jug back on and use an impact driver on the flywheel nut (tightening). that impact should transfer to the piston and loosen it up a bit, allowing 1 & 2 aboev more chance of success. repeat in series it'll work more fluid in and work the piston loose.

The grease method works but only if the piston is above the ports.

I bet you can twist and smack it loose with a socket on the flywheel, just go both directions, give it some good hammers

but yea cutting it off it a decent option too since you prolly oughhta just replace the crank anyway