Piston stuck in cylinder

[eightsevenzero]

So i started disassembly on one of my CB400T blocks and all went well until i couldnt get the second piston out. the first one just popped right out when i was removing the jug cylinder but now i have the right one still lodged in. not sure what to do, ive used every different type of lubricant to try and budge it, ive tried hammering on it from the top applying even pressure to the whole head at once, but its like its fused in there. any suggestions? i was just thinking of ditching the jug cylinder portion and that piston but id like to save the rod if i could but i dont see a way as of right now...

 

[VonYinzer]

Fill the cyinder with kerosene and let it sit like that for a couple days. See if that frees it up.

 

[Woosey]

use penetrating oil.. i prefer PB blaster but any should be fine

let it soak for a couple days.. if you dont have the piston,rod and cylinder off the crank, you should to avoid damaging anything... then use an appropriate size block of wood and hammer the piston out.. you can either have someone hold the cylinder firmly or build a little rig to hold it

i have used this teqnique on rusted pistons as well as seized pistons and havent had a piston not free up

the cylinder will most likely need to be bored and the piston will be unusable

 

[jay_kent]

Swan had a post about filling cylinder with diesel fuel and atf then lighting it on fire. The heating and cooling unfroze the piston.

http://www.dotheton.com/forum/index.php?topic=20929.90

 

[eightsevenzero]

I've tried pb for a day and a half
But I guess I could let it sit for 2-3 days, but I sure do love setting stuff on fire....

Yeah the cylinder has been separated from block so all good

 

[VonYinzer]

You could always try freezing it too...

 

[Woosey]

idealy.. before you hammer on it you could flip it upside down.. fill the piston with ice then put a propane tourch to the cylinder to expand the jug and not the piston

 

[swan]

I had a severely frozen piston (40 years of sitting), tried all the usual lubricants for months until I tried the following and it worked great! http://www.dotheton.com/forum/index.php?topic=23057.0

 

[crazypj]

Burning stuff only works if it's a solid block. CB/CM 400 has liners in alloy *and not very tight ones in my experience)
Burning will probably loosen liner without loosening piston