Author Topic: Stuck #2 piston (Read 2088 times)

BlindSight · « **on:** January 08, 2011, 12:31:11 PM »

SO im sure alot of you have already helped me through my other stuck piston problems and now im down to it...the head is removed and now im trying to pull the cylinders off. They raise up enough for 1&4 to come out and #3 looks like its free when I move the block it moves a bit but #2 is in there stuck and I cant get it all the way off. It soaked in ATF/Acetone for almost a week and now its been soaking in liquid wrench for 3 days. I have heated it up with a propane torch, then pounded on it with a hammer and wooden block...then with a big socket and a hammer...still nothing. Any other ideas? it sucks because 1&4 look great, no rust at all, nice and oily and very minor carbon on top...assuming there must have been some kind of leak on 2 or the spark plug was left out or not sealed tight or something and thats why its the only one like that?

Hush · « **Reply #1 on:** January 08, 2011, 12:45:26 PM »

Only persistance and pure dumb luck will win you this one mate.
It may be that the #2 piston is at the very end of it's travel down so pounding it will only micropene (or totally root) it.
As I assume you are going to lift the barrels once you have that piston free you could reuse those small wedges and place them this time between the bottom of the barrels and the lower casing.
It may lift the barrels just enough to give that piston some downward play and it may break free.
Don't go in under the barrels or you might ruin the seal between the casing and the bottom of the barrel, try to go alongside (especially the #2 barrel side) below the fins.

As before "should any of your efforts lead to breaking parts of your 500 the secretary will disavow any knowledge of your actions"----and for God's sake don't tell TT about my caveman ways!!!!

Hush · « **Reply #2 on:** January 08, 2011, 12:49:17 PM »

Just had a thought, is it Winter in your part of the world?
You see heating the piston will only make it swell as alloy (the piston) expands quicker than steel (the barrels).
You could drop the whole motor into a chest freezer for a few hours or bury taht sucker in a snow drift!

Just don't forget where you burried it.

Mark M · « **Reply #3 on:** January 08, 2011, 12:50:54 PM »

HEat and quck cool may break the seal,
Heat up with your torch then fill the pot with ice water, or if you can get it dry ice is good stuff.
If it fails the first time then repeat for a few heat/cool cycles.

BlindSight · « **Reply #4 on:** January 08, 2011, 12:58:48 PM »

yeah the piston is at the very bottom of its travel....and I live in texas and its around 60 outside so going to raid the ice trays in the freezer and give that a shot.
THANKS FOR ALL THE QUICK REPLIES.

Shoeboxjoe · « **Reply #5 on:** January 08, 2011, 01:11:19 PM »

I've had some luck in the past with PB Blaster and heard others prefer Marvel Mystery Oil for soaking stuck pistons. Put a wrench on the crank and give it a little pressure slowly until it breaks that seal then work the cylinders off. Patients is the key, walk away when you get frustrated and come back to it later.

camelman · « **Reply #6 on:** January 08, 2011, 01:49:07 PM »

Save the ice for after you heat it. Get it good and hot, then drop some cubes on the piston. Water would probably work just as well. Dry ice would be fun, but it doesn't have much heat capacity, so it won't cool the piston as quickly as water/ice.

Camelman

camelman · « **Reply #7 on:** January 08, 2011, 02:00:59 PM »

I was just thinking about application methods for the water. If you can't break it free with the heat and water/ice method, then try making a shield out of sheet metal that will fit into the cylinder to keep water from contacting the cylinder walls. Heat the piston and cylinder up before inserting the shield. That should help keep the cooling effect off the cylinder walls.

Camelman

Kevin400F · « **Reply #8 on:** January 08, 2011, 02:03:27 PM »

If the engine is out of the bike, separate the crankcase halves, unbolt the connecting rod cap on #2, and lift the cylinder block off along with the stuck piston and the connecting rod. You should then be able to rig up a way to press the piston out of the block.

Spanner 1 · « **Reply #9 on:** January 08, 2011, 02:08:44 PM »

Are you sure its not #2 conrod big-end bearing seized.... that will stop all efforts to move your #2 piston

BlindSight · « **Reply #10 on:** January 08, 2011, 04:42:22 PM »

So...with the help of a couple ratchet straps under the center section and around the frame I supported it up and used the socket and hammer and beat it out after some good heating followed by some ice water chilling. Now....all of the pistons look fine but will need to replace the rings. all of the cylinders look fine except #2 has some rough rusty spots where the piston was stuck. Will I have to get them bored out or could I gust use a hone and leave them how they are?

camelman · « **Reply #11 on:** January 08, 2011, 05:03:04 PM »

Congrats!

I've seen bores that look like hell come out fine with a hone job. The only way to know for sure is to measure the bores though. Take it to a machine shop and have them mic it top/center/bottom, and do it for each cylinder. You want front-to-back and side-to-side measurements. Do that after you hone it. If it checks out, then you just need new rings. If not, then you'll need to bore and install new pistons and rings. There's a guy on the forum who'll do it for $45/hole plus $20 for shipping. Pretty good price.

Also, check your pistons to see if they have worn. If the skirts are worn, then they will rock in the cylinders which will yield low compression and quick wear.

Camelman

MCRider · « **Reply #12 on:** January 08, 2011, 05:21:36 PM »

A 50/50 solution of acetone and ATF is by far a better penetrant than anything mentioned so far, by a factor of at least 2, maybe 4. (according to an engineering article that is floating around in the archives) Many here have used it to free up engines. Yours may be past the point of any penetrant, but thought i'd make the offer.

BlindSight · « **Reply #13 on:** January 08, 2011, 06:40:36 PM »

thanks, I have a micrometer so will start measuring them asap and go buy a hone...the #2 doesn't look to bad so hopefully I won't have to bore them out. If I just hone they cylinders do I just go for standard sized rings or will I need like +.025 or something?

camelman · « **Reply #14 on:** January 08, 2011, 07:26:57 PM »

If all you do is hone, then install standard rings (assuming your cylinders haven not been bored yet).

Someone on here should be able to tell you the limits for your cylinders. I don't have info on the 550.

Camelman

Hush · « **Reply #15 on:** January 08, 2011, 11:40:51 PM »

Well done that man, he's now a total addict ha ha ha...........

wrenchmuch · « **Reply #16 on:** January 09, 2011, 01:17:09 PM »

After you hone check your #2 bore carefully under strong light . Look for any pitting left by the rust where the ring was stuck . Pitting will speed up wear on your new rings .

BlindSight · « **Reply #17 on:** January 09, 2011, 01:53:30 PM »

Will do, thanks for the tip, anyone know what kind of hone I need size and type? its a 500/4

camelman · « **Reply #18 on:** January 09, 2011, 02:59:16 PM »

You can probably get one at your local Kragen/Autozone, etc. Just make sure you get one that is sized for your bore. Then, read about how to do it and watch some youtube videos (I'm just assuming someone has posted by now). It isn't rocket science, and you can actually do it by hand with emory cloth, but make sure you understand it before jumping in.

Camelman

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Author Topic: Stuck #2 piston (Read 2088 times)