got the head off #1 piston stuck in the bore help!

zukdave wrote: Raise the cylinder block about 1" off the case and there
should still be enough stud to bolt a plate to.
Make the plate so you can still get a torch inside
the cylinder and apply heat to the TOP liner not the piston.
As the heat runs down the liner it will expand and let go of the piston.

Worst case I did use an air chisel one time to get a GT750 cylinder off the studs
for the crank.

Cool, but I still don't get the plate. If I lift the cylinder up 1", and put a plate on top and start tightening the nuts, the cylinder's just gonna drop down again. If I use shims to keep the cylinder raised with a 1" gap between the cases and the cylinder, then start tightening the head down, sure the cylinder won't plop back down on the cases, it's held up 1" by the shims, but all I'm doing then is squeezing the cylinder.

What am I missing?

basically what you're doing is building a puller like a steering wheel puller or harmonic balancer puller, use the studs to hold the plate on, and a bolt in the middle to press down on the piston.

If you look up harmonic balancer puller you can get the general idea. Apparently I'm no good at explaining, os so my wife tells me.

floivanus wrote: basically what you're doing is building a puller like a steering wheel puller or harmonic balancer puller, use the studs to hold the plate on, and a bolt in the middle to press down on the piston.

If you look up harmonic balancer puller you can get the general idea. Apparently I'm no good at explaining, os so my wife tells me.

I get it, there's a 'pusher' bolt between that plate and the piston to push down on the piston. At least I *think* I get it. Here's what I think I need to do:


1) rotate the crank to get the piston in the middle of its stroke

2) the cylinder will move up off the block because it's stuck to the #1 piston; ie. as we rotate the piston to mid-stroke, there's a gap created between the cases and the bottom of the cylinder because the cylinder moves upward with the piston stuck inside the #1 bore

3) make wood shims to hold the cylinder up off the block, this will keep the cylinder from moving down when we start pushing downward on the stuck piston

4) we're positioning the piston in mid-stroke to give it room to move downward when we start pushing down on it and it (hopefully) un-sticks from the bore

5) now measure the distance from the top of the stuck #1 piston to the top of the cylinder and find a long bolt that is a bit longer than that measured distance -- this 'pusher' long-ish bolt will be used to push down on the stuck piston -- we'll push down on the 'pusher' bolt with a metal plate that we place on top of the cylinder; the metal plate has holes drilled for the cylinder studs to slip through and the head nuts are used to apply pressure to the plate which will then push down on the 'pusher' bolt and on the piston.

6) I'm wondering if a piece of 2x2 lumber would be safer as a 'pusher', since if the 'pusher' bolt slips it's gonna score the wall of the cylinder. Maybe experiment with that first.


7) put some acetone+antifreeze down that dang hole and start tightening that plate!

Ok, im my opinion the block is toast and will need to be bored at the least to be used again. The rust goes deep and cannot be cleaned out, it will need to be bored and honed. Use a torch and heat the thing up! If your using the advancer bolt to try and press a stuck piston out your going to break the locating pin off in the crank.

etbike3135 wrote: Ok, im my opinion the block is toast and will need to be bored at the least to be used again. The rust goes deep and cannot be cleaned out, it will need to be bored and honed. Use a torch and heat the thing up! If your using the advancer bolt to try and press a stuck piston out your going to break the locating pin off in the crank.

Understood, my buddy's coming over tomorrow with his gas welding gear, no way am I sacrificing a crank pin for a stuck piston.

Dont think i ever mentioned the crank bolt i said crank on a bolt. Used this method on a 175 honda 350 honda and a 650 kaw last summer alone.

floivanus wrote: Dont think i ever mentioned the crank bolt i said crank on a bolt. Used this method on a 175 honda 350 honda and a 650 kaw last summer alone.

Yeah, I was wondering where the crank pin came in too.

Folks, I went and bought a blue bottle of plumber's gas, a nozzle for the bottle, and a what they called a 'striker' at Home Depot to light it.


I really want to hear how you folks did this heat trick -- what are the steps? I'm 100% in the dark as to what you do -- do you put the flame on top the piston then hit it with a wood block?

What are the steps you have used successfully to free a stuck piston with a flame and hammer?

Make sure no gasoline or flam material is anywhere around flame.

Heat makes things expand right! so if you heat piston top ....well ... that will expand the piston? do you want that.

The bottom of jug/cyclinder has rubber plugs in it so watch them when putting flame to this area.

I have no experiance doing this so for where to put flame / heat up, I will leave to people in forum who have done it.

Good luck.

As 4theKZ mentioned the part you heat will expand. Being it is all aluminum it will transfer the heat easily also. I would heat the piston and then cool it rapidly. Hope fully a few times of that will break the bond with contraction and expansion.

The cylinders liners are steel and heating the block is how they are removed so you will need to be careful there. They also have o rings in them I think. Hopefully someone will chime in here.
Wayne

newOld_kz1000 wrote: The entire cylinder moves up and down with the #1 piston! The other pistons are free in their bore.
Here's what I've tried so far:
1) penetrating oil bigtime on #1, dousing and dousing, liberally
2) put some household oil right in behind the Amazing Blaster
3) have whacked on the top center of the #1 piston using a big rubber mallet on a wood stake
4) put the bike in its top gear and rocked it, kicked it with kick starter, that dang #1 piston won't come free
I felt the #1 bore and it doesn't feel bad, and the bike had sat for years, and initially the other pistons were also stuck but they're free, it's only this #1 piston.

I am tempted to let the #1 piston and cylinder rise up off the crankcase, then lodge a wood block between the bottom of lifted-up cylinder and the cases, one piece of wood in front and one in back, then rotate the crank so it's not at TDC and whack that dang #1 piston like a stepchild.

Any other ideas?

let the #1 piston and cylinder rise up off the crankcase, then lodge a wood block between the bottom of lifted-up cylinder and the cases, one piece of wood in front and one in back, then rotate the crank so it's not at TDC and whack that dang #1 piston like a stepchild.

Likely the piston rings are rusted frozen to the cylinder sleeve (and not so much an issue with the piston itself being frozen to the cylinder sleeve).

With the mentioned setup, would flood the cylinder with "Kroil," if available, otherwise a 50-50 mixture of acetone and ATF. If desired, may catch the run-through with a shop towel, or allow it to drip into the crankcase (for later rinse-out). Keep re-filling as needed for assuring a continuous generous supply of penetrant to the area where rings are frozen to the cylinder sleeve. At least overnight, and a few days would be even better.

When whacking the piston, would use a large wood dowel or length of 2x2 (conformed as possible to best fit shape of the piston crown).
My whack tool of choice would be dead-blow hammer.

Am thinking that application of heat before whacking would do more harm than good, as the aluminum piston would expand tighter against the steel cylinder sleeve.

Could also apply dry ice to the piston crown, just before whacking. Might help toward ever so slightly shrinking the piston, relative to the cylinder sleeve.

Good Fortune!

Okay, I've tried everything and am going to sacrifice that piston to get the cylinder off the block. That aluminum piston's probably distorted anyway with all the pounding etc. it's taken over the past few days.
I was not at all planning to reuse it.

How can I safely 'disassemble' that piston while it's stuck in the bore? I'm wondering if drilling successively larger holes in the top of the piston would do it, weaken it up, to get the jug free and clear -- put a rag to catch anything from falling into the crankcase.

Is that the best way?