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Post by rowdy235 on Feb 15, 2019 22:38:34 GMT -5
Got the saw torn down tonight. Looks like something metal went through it. Has a 1/2 wide groove from just below the exhaust port to nearly the top of the cylinder. Fortunately the bottom end seems okay, but will inspect closer tomorrow
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Post by edju1958 on Feb 15, 2019 23:08:40 GMT -5
So,at the least you're looking at a new cylinder & piston kit.Right? Ed
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Post by rowdy235 on Feb 16, 2019 0:07:44 GMT -5
^ Yes, definitely a new cylinder and piston kit are in order. However, on the bright side, I think that should be it. The bottom end seems good, actually, I'd even say exceptional. All the bearings are very smooth. The connecting rod bearing seems a little "loose" but IIRC (been a long while since I've had a saw down this far) that is by design so plenty of oil will get into the bearings? I also need to replace the fuel hose (crumbled when I disconnected) and rebuild the carburetor, but one thing at a time. It honestly seems like this failure occurred when the saw was relatively new. Its in such good shape cosmetically and there is very little "junk" in any of the normal hiding spots. That combined with the shape of the bottom end and I don't see this saw having that much use. The big question on my mind is what went through the saw and how did it get in there? Of course, carnage pics:
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Post by 5terrysupersaws on Feb 16, 2019 0:59:48 GMT -5
Is the lower ring broken or is the gap locating pin missing and thus allowed the ring to rotate and catch the exhaust port ? Need a pic of the other side of piston. I enjoy failure analysis.
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Post by rowdy235 on Feb 16, 2019 10:43:36 GMT -5
Is the lower ring broken or is the gap locating pin missing and thus allowed the ring to rotate and catch the exhaust port ? Need a pic of the other side of piston. I enjoy failure analysis. Me too! Both rings broke when trying to remove but looks like about a 1" chunk of the bottom ring is gone... what could have caused that? Both locating rings in place
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Post by edju1958 on Feb 16, 2019 11:17:58 GMT -5
Being that the saw was used for cutting concrete,I think that somehow it ingested a piece of concrete,rather than a chunk of metal.Running the saw without a filter by a complete moron would do it. Ed
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Post by rowdy235 on Feb 16, 2019 18:09:05 GMT -5
I think you may be right on that one Ed.
I have been making a list of parts I need for the saw. The fuel line is pretty much shot in fact there isn't even much of a fuel line inside the tank anymore. I read elsewhere somebody used Tygon and replaced the whole line from the carb to the filter, what does everybody think of that vs using the OE in tank line, hard piece, and connector piece to the carburetor?
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Post by rowdy235 on Feb 16, 2019 18:34:49 GMT -5
Also, I am trying to figure out which cylinder I need. Mine is stamped 48796, but I see several others ones listed. Would a 69644 also work?
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Post by edju1958 on Feb 16, 2019 18:55:29 GMT -5
If the fuel line is anything like the SXL-925,Leon has the two piece line kit with the grommet for the tank.I also read about someone doing a one piece tygon line.I don't know how that'd work with that sharp turn into the tank. Ed
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Post by Clasec on Feb 16, 2019 21:26:28 GMT -5
Also, I am trying to figure out which cylinder I need. Mine is stamped 48796, but I see several others ones listed. Would a 69644 also work? Yes a 69644 will work.It's an oval port exhaust cylinder and 2 1/16 bore. 69644 cyl. by Clasec, on Flickr
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Post by rowdy235 on Feb 18, 2019 11:55:31 GMT -5
Thanks guys!
Though it wasnt easy I think I have everything I need en route. Hoping to have by the weekend! Actually ended up finding a nice cylinder/piston locally so just had to order the gaskets/bearings/etc.
Stay tuned!
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Post by edju1958 on Feb 18, 2019 14:06:11 GMT -5
Gled to hear you got what you needed locally. Ed
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Post by rowdy235 on Feb 21, 2019 20:04:57 GMT -5
Picked up the cylinder/piston today. I have to say I was skeptical when the guy said like new but I believe him. And the first round of goodies showed up
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Post by rowdy235 on Feb 22, 2019 23:52:54 GMT -5
Got all the parts in except the carb kit. Kind of a bummer but at least this way I can get the saw mostly reassembled. Hoped to get further tonight but darn gaskets held me up. Since my base gasket stuck to the saw and the cylinder I bought came with the base gasket stuck to it, I got the privilege of removing both. The saw side was fine, little heat, little scraping, came right off. The cylinder not so much. I tried heat, scraping, various brushes and solvents, and ended up having to finish up with some fine grit emery cloth. All in I think it took about an hour and a half, but the result was good IMO. Tomorrow begins reassembly!
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Post by rowdy235 on Feb 23, 2019 12:44:41 GMT -5
I was antsy to get going this morning so hit it early! First order of business get the piston and rod reinstalled with new bearings. I know there are several ways of doing the rod bearing but I wanted to share my method. First I use a decent amount of grease and install 14 bearings in both the rod and the bottom cap. I then turn the crank to BDC and use a pair of needle nose to hold the bottom cap, putting it in with the top facing forward, making sure the grease holds it in place. Once in I rotate the crank to TDC and fish some wire in behind the cap to hold it while I lower the rod down and put the screws in. I also use a dab of loctite on each screw. Since this saw has the washers on the piston end to center it, I find it easier to install the piston to the rod first and then install the piston/rod onto the crank. After installing the cylinder and torquing it down I began reassembly of the saw. I knew I was going to forget something and today I figured out it was a reed gasket. Nothing a couple minutes and some gasket material couldn't solve. I then went ahead an reinstalled the rear handle portion. There is a gasket that goes between that and the rest of the saw that is about impossible to find, so some high-temp RTV had to substitute. I figure all it does is prevent junk from getting around the air filter so actually probably a good place to use RTV. Starting to look like a saw again! I going to do the fuel line and get a recoil handle today, the rest will have to wait until my carburetor kit arrives!
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Post by rowdy235 on Feb 23, 2019 17:08:43 GMT -5
Well guys the project has hit a snag.
When turning over, the engine "hangs up" at TDC, almost like the piston is being pushed just a little bit too far up. Think I'm going to have to pull the cylinder and see if anything is amiss, but I'm guessing I may need some sort of spacer to go at the bottom of the cylinder. It seemed like the gaskets that were on there were much thicker than the replacement one I got.
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Post by 5terrysupersaws on Feb 23, 2019 17:36:40 GMT -5
Measure the squish before pulling it apart to verify that's the problem.
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Post by rowdy235 on Feb 23, 2019 18:04:27 GMT -5
^ Well, it actually wasn't the problem. I looked every way from sunday trying to figure out if the problem was not related to the cylinder/piston but kept coming up empty. As a last resort I went ahead and pulled the cylinder back off. Turns out a piece of the exhaust gasket, maybe 1/4" long had broken off and found its way over to the intake side of the piston, out of sight from both the exhaust port and the spark plug hole. It was a little humbling to have to take the saw back apart to see that but I am eternally thankful that it caused the issue, because I am sure it would have wreaked some major havoc had I ran the saw with that in there. Now that I am well versed reassembly went much smoother First thing I did after reassembly was to pull it over and all is good. Phew. Put a spark plug in and pulled it over and man this thing has some compression! I (more appropriately- my shoulder) could use a decomp valve haha. I went ahead and got the rest of the saw buttoned up, starting with a new tygon fuel line and new filter. Prior to that I filled the tank about 1/2 way with seafoam and shook it for a few minutes, seems to have cleared all the old fuel / oil / gunk out nicely. At this point I'm on hold until my carburetor rebuild kit arrives. I am also not going to chance it and order another muffler gasket. I guess it just goes to show that Murphy is always with you and you have to keep alert at all times. Fortunately this one appears to be no harm / no foul.
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Post by edju1958 on Feb 23, 2019 18:24:02 GMT -5
Glad to hear it worked out in your favor. Ed
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Post by rowdy235 on Feb 23, 2019 20:00:41 GMT -5
Just some pics of the progress New Starter Handle- just a universal job. I like these handles from Ace Hardware, they have a big grip. Tygon Fuel Line (almost matches the saw!). Also have new in-tank line and filter
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