Stihl MS311 Cylinder Options

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Joey87

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Hi all! I’m new here and have searched for an answer with no luck. I had a crank bearing fail on my MS 311 and trashed the piston and lightly scored the cylinder (enough I can barely feel it with my finger). New cylinders appear to be $300 plus so was wondering if another Stihl model has a cylinder match or what options I have. Any help is much appreciated.
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Cylinder has a small chip on the exhaust side port so I’m afraid a ring may hang up in it if I just replace the piston and rings. Still toying with the idea of trying it but don’t want to waste $30 on a piston if it snags on the chip.


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I would probably take a Dremel and smooth it down a bit but it could be used. If it was to the side of the port I would say no. The cylinder shouldn't be used unless you smooth the walls down a bit, I generally use #400 or higher automotive sandpaper, sand crosswise in the cylinder, never up and down..
 
Well I got the 311 put back together today after I had cleaned up the cylinder. I purchased a new piston and ring set ,crank and flywheel off a newer saw (all looked great) I got off eBay, new fuel filter and spark plug and it started up and runs great for a grand total of $85 in the saw. I guess the two small chips above and below the exhaust port were ok after the clean up. I depressed the throttle fully, popped out the decompression valve, and show a compression reading of right at 130. I don’t know if thats good, bad, ok, or about average. Anyone have an idea of what a good compression test reading for a Stihl MS 311 should be and did I do the test right with the decomp valve popped out and trigger depressed?
Thanks for any feedback
Joey


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Yeah, 130 is a bit low for one of those but it may come up when it's broken in a bit. I usually don't open up the throttle when I test compression but probably a good idea. Air comes in through the intake and the exhaust on a two stroke so it's not much different with throttle open or not. Sometimes the de-comp leaks a bit on some saws also..
 
Most saws from that series are about 140 to 150 once broke in. With a woonded jug you are ok at 130. Testers have variables too. I think you are safe as long as you knocked down any high spots near that chip.
 
Well I got the 311 put back together today after I had cleaned up the cylinder. I purchased a new piston and ring set ,crank and flywheel off a newer saw (all looked great) I got off eBay, new fuel filter and spark plug and it started up and runs great for a grand total of $85 in the saw. I guess the two small chips above and below the exhaust port were ok after the clean up. I depressed the throttle fully, popped out the decompression valve, and show a compression reading of right at 130. I don’t know if thats good, bad, ok, or about average. Anyone have an idea of what a good compression test reading for a Stihl MS 311 should be and did I do the test right with the decomp valve popped out and trigger depressed?
Thanks for any feedback
Joey


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