1974 penton 250 Stuck Jug

[herman]

Could some help me as i have just bought a 1974 250 and i got the head off and can not get the jug off Me and the person i bought it from do not now the history of the bike the piston had almost no carbon on it and the piston says 71 so i am asuming that its still on standard bore.the kicker will not work as i believe this problem is from the froze piston any help would be very helpful. thanks Herm

[Doug Wilford]

First let it soak in a penetrating oil

[herman]

Thanks Doug, thats what iam doing with it right now. As i look up in the exaust port i can see rust there not a lot.And on the intake side i can see a little rust there too.Will the rust that iam see be the problem? Thanks Herm

[DKWRACER]

If you can get the studs out, and after the penetrating oil has had time to sit, you can very carefully rotate the cylinder maybee 1/8 inch, DO NOT USE TO MUCH FORCE, the intent is to just break the piston free, take your time too........

[Kip Kern]

Herm

I have had luck with the PB Blaster soak, then driving the piston out with a round copper drift and dead blow hammer while supporting the cylinder in my lap and allowing the bottom end to hang free over a rubber pad.  If it is a tough one, I have disassembled the entire bottom end and pressed out the piston in my press with the crank assembly hanging in free air.  Either way works.  Your rings are probably rusted to the cylinder walls so kiss them goodby and get ready for a bore job and a new piston!

[herman]

Kip thanks for the information.Mark Seals says hello he came up to pick up a 76 400 that i had.

[tlanders]

The best penetrating oil is Kroil Oil made by Kano labs. Go to http://www.kanolabs.com. It's incredible stuff.

Teddy

[dirtbike]

There are many oils that will solve the rust in a good way. I was thinking, is the ring below or above the ports in it's current position? I would use a small wood piece and bang it out but in that direction so it won't catch the ports more then neccesary. In other words, is it stuck below the ports, bang it downwards, otherwise take it out on top. The piston might could be saved. With a bit more luck than to expect, even the sleeve. The rings has to go for sure though.

Do we know that it hasn't seized? In that case it can be really hard to get it out!

[herman]

Well thanks eveyone for your help.I ended this with taking it to Lake cycle(old penton dealer in Grand Haven Michigan) They got it a part and the whole bottom was full of water.The crank was also froze as well as all bearing.All the cases were all a powdery white from 25 plus years of corrosion.The person that i bought it from said he would stand by the bike if i had a major problem with the engine and He did he is sending me a good used bottom end .The cylinder after getting the piston out was all pitted from the piston skirt down (realy deep pits )So even though it was standard bore they said it need a new sleeve.The people on this site and the members are the Best for helping a person with a PENTON .Thanks And Happy Christmas Herm Knoll