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Me, Im picking part of cage from the bottom rod bearing- they can be tricky to see, bearing feels "good ish" and it gets ya twice
Stihl MS 390 carnage - disassembly.
- Thread starter MacAttack
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Me, Im picking part of cage from the bottom rod bearing- they can be tricky to see, bearing feels "good ish" and it gets ya twice
Get those seals off so you can CLOSELY inspect those bearings. The advice given here is from years of experience.
I washed the piston and crankshaft from a MS660 in the dishwasher last week. Get any grit out. Washed the cylinder as well. Odd job because the top end and crankshaft were good , but both crankcase haves needed to be replaced.
Anyway, if you go that route with the dishwasher spray the crankshaft and bearings with your choice of oil pretty quick when it is dry.
Should clean any junk out.
Anyway, if you go that route with the dishwasher spray the crankshaft and bearings with your choice of oil pretty quick when it is dry.
Should clean any junk out.
I'll take a closer look at the bearings before i put it back together. I wonder if they were already replaced at some point because they have metal races instead of plastic.
I'll get in there and take some pics. I couldn't find any metal bits in the engine, it seems to me like it got hot and started to eat the piston, and add in some carbon scoring.Me, Im picking part of cage from the bottom rod bearing- they can be tricky to see, bearing feels "good ish" and it gets ya twice
Also, I didn't mention yet but I think I know why the saw burned down. There was no sign of gasket material / silicone on the cylinder base. It's as if it was taken apart, bearings replaced, and reassembled without sealant. I'm not sure what to make of it....
Existing bearings just say "China HR8 6203"... I'm guessing that's not good?
Are these SKF bearings a suitable choice if I remove the seals?
https://a.co/d/bn6jikz
Are these SKF bearings a suitable choice if I remove the seals?
https://a.co/d/bn6jikz
Junk bearings.
Carefully inspect the rod bearing for cracks
Carefully inspect the rod bearing for cracks
What are your thoughts on the SKF bearings I found?
Those are fine
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Yes they are- they are the correct C3 type and when using these personally, I use a small pick to remove the dust shields and expose the cage before fitting.
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Could be the previous owner replaced the bearings that caused the damage we see and neglected to seal the cylinder down and simply replaced the bad broken bits, used same piston and probably rings, then promptly sold it- without a pressure and vacuum test prior to stripping, there is no true way of knowing if it leaked bad there and was causing issues- probably was- but no proof only guess work.
SKF bearings on order.
I suppose it's not worth leaving in China bearings of unknown quality for $17 in SKF bearings.
I suppose it's not worth leaving in China bearings of unknown quality for $17 in SKF bearings.
You could be 100% right. People do some strange things. You can even see remains of the original gray silicone in the cylinder base bolt holes that was scraped away and not replaced. Nothing I can do except replace with good parts and put it back together correctly and see what happens. I will say, the saw does not seem like it has a lot of hours on it...
