Topic: Removing a frozen piston.

[goaarongo]

This thing was STUCK.
Check out all the nasty nasty stuff inside...



I pounded, pried, cussed and spit, drank a beer, and did everything I could think of that would not damage the cases.  Halfway considered putting an angle grinder all the way through the cylinder, but that seemed excessive.  Then an idea...

Went to O'Reily's auto parts and got the biggest gear puller they have.  They loan them out, so it was free after they added (and then removed) a $60 dollar charge to my credit card.
It fits perfect.





I tossed in one of the largest sockets I could find handy, so I didn't actually have to ruin the piston (not that it was worth much anyway).  It also helped center the tool and distribute the pressure more evenly.  Think you can see it in this shot:



A few cranks of my wrench, and done.  No broken fins, no dinged cases.  Free.  Sweet.

   

 

[750goes]

very smart move - sure was rusted in there as well -

[750goes]

and that rod is rusted to hell as well - how much water was it sitting in ??

[goaarongo]

It had been sitting by the side of a barn for god knows how long.  I also found a pretty large nail inside the cases for some reason...

[Blasbo]

Good trick. I may have to use it when I try to un-stick mine.

[fastbroshi]

I wonder if it would be able to reach the inside pistons.  A third arm need to be anchored somewhere to keep it from spinning right?

[digiacomo racing]

great idea, just got a 750 that will not turn over. the old owner said he rode it parked it and it sat for 15 years. so i think i have the same problem

[goaarongo]

Thanks for the props - I was pumped when I figured this one out. 

I wonder if it would be able to reach the inside pistons.  A third arm need to be anchored somewhere to keep it from spinning right?

The trick is finding a gear puller that has 4 arm positions.  No matter which cylinder you are working on, you need two arms that are lined up at 180 degrees.  I did use the third arm on mine (since I was working on an outside cylinder) but you probably only need the two.  The arms come off with no trouble, so I would just remove the third one to try one of the inside pistons. 

Hope it works for you.

[kayjohn]

Good idea. I have one that is stuck REAL bad. All four. Think I'll try two pullers at the same time. Problem is getting under the cylinder it looks like.

[PPG9944]

Just tried this.  Worked like a charm!

[Oldtech]

I've been messing with old junk for dacades and I've unstuck many engines with a small special too I make.

 First you have to bolt the cylinder and head back down with the cam out so that all the valves are closed. I have a collection of old spark plugs of different sizes where I've knocked out the center insulator and electrode so that the hollow plug body is all thats left. I then find a bolt that is slightly larger than the center hole and thread the plug body to take this bolt. The bolt is drilled through lengthwise and a grease fitting threaded into the end. Thread this into the plug hole and put a grease gun to it. Some grease guns can develop 10,000psi and this is more than enough to break most pistons loose without damage to anything.

 I also have a collection of bolts of various sizes and thread pitches that are drilled through and threaded for a grease fitting to break loose brake caliper pistons when compressed air won't work.

[mrbreeze]

Yep. The grease will work great so long as there is a real good seal. I have the tool for taking a pilot bearing out of a crank on a car engine using the grease gun.

[CycleRanger]

Similar to this solution that uses a steering wheel puller.
http://www.hondatwins.net/forums/55-engine-discussion/34218-seized-honda-cl450-motor-sat-outside-over-30-years.html#post271149