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Seized Two Cycle

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I have a Yamaha DT175 1980 with a frozen piston.  It froze from sitting for 30 years and did not seize while riding.  I have the head off and put a bunch of lubricating oil in the cylinger.  If I can't kick it free with the kickstarter is it a bad idea to hit the crank with an impact wrench?  If so, what should i do?  I am likely raking the engine off the bike anyway.  Should I wait until it is off and tap it with a block of wood?

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I would spray it down with marvel misery oil, let it sit over night and try to kick it then. If you can't get it, the using a piece of wood on the piston and striking it with a dead blow hammer would be next. Good luck

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I would try a 50/50 mix of ATF and acetone and would tap it with a hammer and piece of wood. Trying to loosen it with the kick starter might cause damage to it. If that doesn't work, order some Kroil. 

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Head, exhaust, carb off, remove the barrel. Carefully!!! Most likely the main bearings are rusted soilid. Then pull the engine, splic the cases, rebuild the crank. Source a OS piston and bore the barrel, if the barrel is salvageable.

 

Please post in the proper section off TT (Vintage). I've moved this post for you.

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40 minutes ago, motoriot1 said:

I would spray it down with marvel misery oil, let it sit over night and try to kick it then. If you can't get it, the using a piece of wood on the piston and striking it with a dead blow hammer would be next. Good luck

By barrel, do you mean the cylinder?  How do I remove it if the piston is frozen inside it?

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34 minutes ago, RickP said:

I would try a 50/50 mix of ATF and acetone and would tap it with a hammer and piece of wood. Trying to loosen it with the kick starter might cause damage to it. If that doesn't work, order some Kroil. 

By barrel, do you mean the cylinder?  How do I remove it if the piston is frozen inside it?

 

4 minutes ago, William1 said:

Head, exhaust, carb off, remove the barrel. Carefully!!! Most likely the main bearings are rusted soilid. Then pull the engine, splic the cases, rebuild the crank. Source a OS piston and bore the barrel, if the barrel is salvageable.

 

Please post in the proper section off TT (Vintage). I've moved this post for you.

By barrel, do you mean the cylinder?  How do I remove it if the piston is frozen inside it?

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Yes, the cylinder.

The piston is aluminum, the barrel, iropn, they will not 'rust together'. They can be stuck by the base gasket and stuck due to rust build up but gentle working will free it. PB blaster or rust dissolver (ie, naval jelly) .

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4 minutes ago, William1 said:

Yes, the cylinder.

The piston is aluminum, the barrel, iropn, they will not 'rust together'. They can be stuck by the base gasket and stuck due to rust build up but gentle working will free it. PB blaster or rust dissolver (ie, naval jelly) .

I had Marvel Mystery Oil sitting on top for a few weeks.  I hit the top and the sides thought the exhaust and the intake with PB Blaster.  Should I hit the base of the cylinder before trying to work it free?

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2 minutes ago, molloyjp said:

I had Marvel Mystery Oil sitting on top for a few weeks.  I hit the top and the sides thought the exhaust and the intake with PB Blaster.  Should I hit the base of the cylinder before trying to work it free?

No hitting!!!! Lift the barrel up.

If the piston is at TDC and the bearings rusted, you will not be able to push the piston down.

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3 minutes ago, William1 said:

No hitting!!!! Lift the barrel up.

If the piston is at TDC and the bearings rusted, you will not be able to push the piston down.

By "hit" i meant "spray".  Should I spray PB Blaster around the cylinder base?

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3 minutes ago, molloyjp said:

By "hit" i meant "spray".  Should I spray PB Blaster around the cylinder base?

Ah, phew.

No, spraying at the base will do nothing, there is a gasket. Spray in the exhaust port. If the reed block is off, you can spray a lot in there but you will need to lean the bike over and possibly flip it over to distribute the PB Blaster everywhere. Though before you put too much effort, see about parts. Crank, barrel, piston, gaskets. It is pointless to take it apart if you cannot get what you need (cost or availability) to rebuild it.

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Remove all the excess oil from cylinder.

Get a fire extinguisher.

Take a propane torch and heat the fins of the cylinder for about 5 minutes. Move the torch all over while heating it up.

Turn off the torch and while hot dump about a 1/4 cup of ATF down the bore. 

Once the cylinder cools wipe up the ATF from inside the bore and repeat the process.

Do this 4-5 times the last time just leave the ATF in.

It should pry off.

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37 minutes ago, Truman Sparks said:

Remove all the excess oil from cylinder.

Get a fire extinguisher.

Take a propane torch and heat the fins of the cylinder for about 5 minutes. Move the torch all over while heating it up.

Turn off the torch and while hot dump about a 1/4 cup of ATF down the bore. 

Once the cylinder cools wipe up the ATF from inside the bore and repeat the process.

Do this 4-5 times the last time just leave the ATF in.

It should pry off.

What is ATF?  Anti-Freeze?  What is the fire extinguisher for?  If the the blows up?

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automatic transmission fluid=atf  fire extinguisher anytime you are waving flames around something soaked in a flammable substance, ie your bike lol

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I've a few times that ATF and kerosene mixed in equal parts and left

to soak in makes a pretty good penetrating oil for rusted fasteners etc.

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32 minutes ago, molloyjp said:

What is ATF?  Anti-Freeze?  What is the fire extinguisher for?  If the the blows up?

Should I take the engine off the bike before trying to remove the cylinder? 

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  Leave the cylinder on the engine and the engine in the bike.Make sure that the piston ring(s) are not just caught in port stopping the cylinder from being removed.

  If the cylinder bore is rusty then..

  The piston rings are rusted to the cylinder bore,

  Put some" Evaporust "(a rust removal product available at your hardware store) on top of the piston and let it soak for a day or two.

Then.. Remove the Evaporust with a rag and coat the piston with a layer of olive oil(yes from the grocery store) and let it soak for a day or two.

  Heat the cylinder up slowly with a heat lamp for a few hours and the cylinder should slide off.

  This is one of those tasks were a little  patience pays off big.

  Good luck

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I need to plug the exhaust valve on a 2 cycle so that I can dump Marvel Mystery oil into a cylinder with a frozen piston.  Any ideas on something that will keep the oil from running out for a day or two?

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