Four Paws
Addicted to ArboristSite
Time for some more cheap tricks. Most of us have owned a 2-stroke with a scored piston and cylinder - be it a sled, a dirt bike, a saw or trimmer. Whether you seized it personally and felt that sinking feeling in your gut, or bought it as a fixer-upper, there is hope to save your cylinder and get away with the cost of a piston kit, a few supplies, and about an hour of your time.
First things first, if your saw is locked up, and won't turn over after it has cooled down - you might as well quit reading. Chances are it is beyond repair.
Okay, you are going to first need to determine why the saw seized. Did you run straight gas in it? Run it too lean? Or is there a possibility there is an air leak from a torn carburetor boot or bad crank seal? If you suspect an air leak, or don't know why it seized, you better perform a vacuum and pressure test. For instructions on how to perform these tests, read this THREAD!
Now that you have determined whether or not your saw has an air leak, and have fixed the problem if you found one, you will need to make a trip to your local hardware store. For this project you will need to buy the following:
*Muriatic Acid - The smallest container you can find will be fine, although it is handy to have around the house, and goes for about $6/gal in these parts - I bought a gallon.
*Scotch Brite Pad - I use the maroon colored autobody pads. They can be bought all autobody supply stores, most NAPA stores, even some of the farm stores carry them. You only need 1 - about $1-$2. Cut a few strips about 1-2 inches wide off the pad, it will make it much easier to work with.
*Q-tips - I sure hope you have these at your house.
*other helpful, but unecessary items are an air compressor and a bucket of soapy water.
Well, if you haven't taken your saw apart, do so. Survey the damage - even nasty looking cylinders can be cleaned up. Your piston is likely junk, take it to the recycler, or use it as a paperweight. Take a Q-tip and dip it in the Muriatic acid, and apply it to your CYLINDER BORE - take care not to get it in the intake, exhaust or transfer ports. The acid will 'eat' the aluminum that has been transfered to the cylinder bore from the melted piston = what you want! But, if you get the acid all down the ports, it will also eat the bare cast aluminum of the cylinder = what you don't want! If you do get the acid where you don't want it, don't panic! Simply wipe it off and rinse it in your bucket of soapy water. Blow dry with compressed air. Re-apply the acid.
This picture shows the cylinder with acid applied. It will fizz and give off an unpleasant odor. The aluminum on the bore will almost flouresce - it is easy to see when the aluminum is reacting with the acid. This is an itterative process - one application won't likely get your cylinder clean. I apply, let sit for a minute or two, wipe off with a paper towel, and re-apply. Repeat as much as necessary until your cylinder comes clean. Feel free to lightly 'hone' with a scotch-brite as you go.
When your cylinder is free of aluminum scoring, give it a quick final hone with a clean scotch-brite. Rinse it in soapy water, blow dry. Slip a new piston & ring in it and make sure it slides freely by hand. If you want to stop here, you are good to go. Install your new piston and rings in your 'freshened' cylinder with ample 2-stroke oil, pour some fresh mix in the tank and go cut some wood.
If your cylinder didn't clean up 'perfect' you can take your cylinder to your local saw/mower shop. If they have a good service department, they will likely hone it for you for under $10. This is a good idea in my opinion, but not necessary. You could also buy your own ball hone for around $30 - a 320 grit, silicon-carbide hone is what you need.
Here are the finished pictures of the cylinder I cleaned up today - as you can see, it is a FAR cry from when I started. I plan on honing it myself when my hone gets here tomorrow.
Hope this helped someone looking to save a cylinder and a wad of cash.
Josh
First things first, if your saw is locked up, and won't turn over after it has cooled down - you might as well quit reading. Chances are it is beyond repair.
Okay, you are going to first need to determine why the saw seized. Did you run straight gas in it? Run it too lean? Or is there a possibility there is an air leak from a torn carburetor boot or bad crank seal? If you suspect an air leak, or don't know why it seized, you better perform a vacuum and pressure test. For instructions on how to perform these tests, read this THREAD!
Now that you have determined whether or not your saw has an air leak, and have fixed the problem if you found one, you will need to make a trip to your local hardware store. For this project you will need to buy the following:
*Muriatic Acid - The smallest container you can find will be fine, although it is handy to have around the house, and goes for about $6/gal in these parts - I bought a gallon.
*Scotch Brite Pad - I use the maroon colored autobody pads. They can be bought all autobody supply stores, most NAPA stores, even some of the farm stores carry them. You only need 1 - about $1-$2. Cut a few strips about 1-2 inches wide off the pad, it will make it much easier to work with.
*Q-tips - I sure hope you have these at your house.
*other helpful, but unecessary items are an air compressor and a bucket of soapy water.
Well, if you haven't taken your saw apart, do so. Survey the damage - even nasty looking cylinders can be cleaned up. Your piston is likely junk, take it to the recycler, or use it as a paperweight. Take a Q-tip and dip it in the Muriatic acid, and apply it to your CYLINDER BORE - take care not to get it in the intake, exhaust or transfer ports. The acid will 'eat' the aluminum that has been transfered to the cylinder bore from the melted piston = what you want! But, if you get the acid all down the ports, it will also eat the bare cast aluminum of the cylinder = what you don't want! If you do get the acid where you don't want it, don't panic! Simply wipe it off and rinse it in your bucket of soapy water. Blow dry with compressed air. Re-apply the acid.
This picture shows the cylinder with acid applied. It will fizz and give off an unpleasant odor. The aluminum on the bore will almost flouresce - it is easy to see when the aluminum is reacting with the acid. This is an itterative process - one application won't likely get your cylinder clean. I apply, let sit for a minute or two, wipe off with a paper towel, and re-apply. Repeat as much as necessary until your cylinder comes clean. Feel free to lightly 'hone' with a scotch-brite as you go.
When your cylinder is free of aluminum scoring, give it a quick final hone with a clean scotch-brite. Rinse it in soapy water, blow dry. Slip a new piston & ring in it and make sure it slides freely by hand. If you want to stop here, you are good to go. Install your new piston and rings in your 'freshened' cylinder with ample 2-stroke oil, pour some fresh mix in the tank and go cut some wood.
If your cylinder didn't clean up 'perfect' you can take your cylinder to your local saw/mower shop. If they have a good service department, they will likely hone it for you for under $10. This is a good idea in my opinion, but not necessary. You could also buy your own ball hone for around $30 - a 320 grit, silicon-carbide hone is what you need.
Here are the finished pictures of the cylinder I cleaned up today - as you can see, it is a FAR cry from when I started. I plan on honing it myself when my hone gets here tomorrow.
Hope this helped someone looking to save a cylinder and a wad of cash.
Josh
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