Partially Stuck 2 Stroke

[CarbsAndCylinders]

I just partially freed up a seized RD350 engine. The pistons now move up and down about an inch or so but will not move through a complete 360 rotation. I am freeing up the barrels now to take them off (they are stuck too) but in the meantime has anyone had a broken ring caught up in a port, a broken piston skirt or bad bearing cause this? I don't want to keep hammering on the pistons if something is "binding".

 

[farmer92]

The last time i tried to "hammer" pistons, shit went down hill real fast.
If it moves, then you will find out when you try to remove the barrels.
Can you look into the ports?

 

[CarbsAndCylinders]

I can't see anything in the ports. I haven't hammered super hard and I have used heat and penetrating oil and after a few weeks got some movement. I will attempt to pull the barrels off tonight, might need a few more days of penetrating oil and heat and some prudent tapping.

 

[odie]

Just be careful pulling the jugs. The cooling fins break real easy.

 

[Spoonz]

Pistons are 180 degrees off in that engine. If you think the crank is seized then pull the bottom end first. Then use a pipe just smaller than the piston to tap on to knock them out.

 

[Hurco550]

For penetrating oil, 50/50 mix of ATF and acetone is the best, seriously. Beyond that, I think the above advice is sounds =)

 

[Tune-A-Fish]

Smash em with a chisel around the wrist pin and yank the jugs off, the holes are shit anyway.

 

[CarbsAndCylinders]

Thanks, guys. I had to go help out a friend and will have to wait until tomorrow but I will split the cases and see what's what. Needs a rebore for sure and I was planning to do the crank anyway cuz I don't know how long since she ran.