A sad state of affairs here. When I was running my XS 029 Stihl on Friday, it felt like it lost compression and was sluggish in the cut. I put the compression tester on it this evening and my fears were confirmed. The skirt of the piston is scored a bit, and it looks like there’s metal flakes imbedded into it just below the dome I’m baffled as to how this could’ve happened. The cylinder itself looks okay, just need to clean some aluminum transfer from it.
How's the cylinder look? Maybe it can be cleaned up and hopefully a new piston & rings will be all you need.
I found the culprit. A whole bunch of hard brown plastic pieces which came from one of the retainers on the crankshaft bearings. You can see daylight straight through the bearing races because all of the balls dropped down. You know what sucks? I saw this morning on CL the same saw for $25, and I almost called the guy thinking I could use a parts saw. Almost… And of course it’s gone now.
A comparison between the ported 039 cylinder (1st picture) and my original 029 cylinder. Note the area around where the crank seals go. The 3 tabs are broken clear off from the bearing debris that got cycled through the motor. This saw is officially toast. If not for the ported cylinder being trashed, I’d redo the bottom end. Now this is just a parts saw. Anyone need 029 parts?
I could. BUT. If I’m going through all the work to redo the bottom end I can’t really justify putting it back to stock. I’m still kicking myself for not putting an 028 super top end on that 028 wood boss I fixed up back in the winter. The 029 is a heavy pig, no two ways about it. At least ported it had a better power to weight ratio. Also getting the motor out, I broke a plastic nipple for the oiler, which is molded into the tank/frame/whatever plastic. So now the number of problems I have to deal with outnumbers the amount of joy I’ll get if I go through all this work. If it was a pro saw I’d approach it with a cooler head in a few weeks, but at this point I’m just done with it.
I've been down similar roads, this stuff sux... Pit of my stomach does flips opening up a saw like that, can't like those posts. Hoping for the best moving forward for you.
Smart move IMO ain't worth the aggravation. I'm thinking a Stihl 462c would nice on your sign line? Just a thought though!
This was briefly on my bench today. Out with the red beard filter that gets squashed by the hood... and in with the Eganperformancesaws.com Uni filter that does not. Unfortunately one ear cracked before I even got it tightened down all the way. They are aware of the problem and have a picture. Hopefully they take care of it. It still functions correctly but if that ear breaks off it won't seal against the carburetor flange correctly. Stuff happens. The design and tool-less removal are nice features as well as the foam being removable from the cage.
As cool as some 3D printed parts are, they can be surprisingly brittle. The engineers at my work have been printing prototypes for years, and are just now playing around with different media/processes that seems to be more forgiving.
I sent pics to a machinist buddy to see if he can replicate it in his machine shop out of something else. Just in case.