400c Rumors… or just internet trolls.

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John got back over there. It was some stihl group. That explains it all. :laughing: =
It was someone on Stihl owners worldwide saying he knows of several that have melted down.

:cheers:
"The saw burned itself up without much warning." While possible I doubt it. These things can and do cover up some pretty nasty airleaks. I just can't buy a saw in good repair with the newer autotune/m-tronic is just gonna lean its self out and you're not gonna have a clue.
 
"The saw burned itself up without much warning." While possible I doubt it. These things can and do cover up some pretty nasty airleaks. I just can't buy a saw in good repair with the newer autotune/m-tronic is just gonna lean its self out and you're not gonna have a clue.
My bad y’all it was Stihl owners worldwide after further review… internet troll.
 
Had mine 2 years now, zero issues. If there was any major issues there should be tons of threads about it by now. Not 25 guys on wastebook crying about one saw that 24 of them have never seen.
That’s why I kinda thought it was crazy Sean, I did my research and knew I was making a good decision about my purchase! But wanted to check with you guys because if anyone knew anything about it AS would!
 
I tagged you there John. I want to see this thread with all these melted down 400's you talk about?

I can only find a couple from the dealers that posted them above. :rolleyes:

New oem piston is only 75 by what a dealer just showed me. Topend kit was 389.

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I’m glad to see all of this I knew you guys would make me feel better! I knew the bs would stop here!
 
That’s why I kinda thought it was crazy Sean, I did my research and knew I was making a good decision about my purchase! But wanted to check with you guys because if anyone knew anything about it AS would!
Mine didn't miss a beat the other day. 5 tanks through it mostly noodling hard dead ash.
20231215_102718.jpg20231215_124456.jpg
 
Found a thread back in Jan 2023. Dealer talking about thinning crews burning them up. They said they think because they dont warm them up. Then just peg them for commercial thinning.

Also just a couple saws not nothing like OP is going on about. He must be on page not group :laughing:

Dealer - I've gotten a few 400's in already from contractors doing commercial thinning and similar work with completely blown up top ends.
Like catastrophic damage, piston grenade inside and taking out both the cylinder and crankcase. All that after just a couple months of use.

OP send me a message with link so I can read this too. Dont seem to be on CR group FB.
It's exceedingly hard to burn up an air cooled motor due to improper warm up. Liquid cooled is a different story.
The other thing is saws just don't burn up for no reason. Especially with Mtronic. Air leaks still happen as with any 2 stroke. The 362 was not a unreliable saw so why would the 400 not be more of the same?
 
It's like a shampoo commercial from the 1970s. Tell two friends, rinse and repeat.

The 400 was the dream of having a bad ass 361 except they cheaped out on bigger crank bearings to save weight. Besides that everything else is quite solid from the real users feedback. I ran two of these when they were factory demos just getting here. Rodney had one in PA quite a few years ago. Somebody else had one that same year. Was lucky enough to be the first one to fuel and run it. By tank two it is starting to come around. Ran one at another gtg broken in and it wasn't too bad in stock trim. Good mids to dig in with a 20" bar. Overall it had the least hiccups of newer models compared to the 661 and 441.
Are bigger crank bearings needed? Some may think so, but often it's not the bearings themselves that contribute to crank failure. It's lack of rigidity in the crank itself. The Suzuki 500 Quadzilla is a great example of this.
The 362 didn't suffer from mass bearing failures that I know off and the 400c has a lighter piston so I'm not sure it's an issue.
 
Are bigger crank bearings needed? Some may think so, but often it's not the bearings themselves that contribute to crank failure. It's lack of rigidity in the crank itself. The Suzuki 500 Quadzilla is a great example of this.
The 362 didn't suffer from mass bearing failures that I know off and the 400c has a lighter piston so I'm not sure it's an issue.
I’ve never heard of 362 -400 bearing failures, rod, pin, or mains. Losing 20% of the piston weight sure didn’t hurt the 400 either
 
Likely it was overheated, pinched the pin and lifted it from the seat hole. Expanded rings grab like vice grips on the ring pins. Notice all the black soot on the sides?
It was clearly overheated.
Doesn't look over heated to me at all. The "soot" you see above the top ring is normal. My 400C shows the same albeit lighter in color.
It's pretty clear to me that it has foreign object damage of some sort.
 
Are bigger crank bearings needed? Some may think so, but often it's not the bearings themselves that contribute to crank failure. It's lack of rigidity in the crank itself. The Suzuki 500 Quadzilla is a great example of this.
The 362 didn't suffer from mass bearing failures that I know off and the 400c has a lighter piston so I'm not sure it's an issue.

I’ve never heard of 362 -400 bearing failures, rod, pin, or mains. Losing 20% of the piston weight sure didn’t hurt the 400 either
A friend gave me his stihl 362C-M, the clutch side crank bearing seized up. The rest of the saw is in great shape. Just need to find the time to put it back together.

I guess this can happen to any saw out there.
 
A friend gave me his stihl 362C-M, the clutch side crank bearing seized up. The rest of the saw is in great shape. Just need to find the time to put it back together.

I guess this can happen to any saw out there.
Usually they don’t seize. If it did, it’s likely from running a dull chain and prying on the dogs all its life and they melted in place. They have plastic bearing retainers to keep the balls in place and those pieces get worn, become brittle and go through the engine eventually becoming melted to the spark arrestor screen.

This is also one of the first things that happens when an oil elitist swears by his “proven” 2 stroke batter at 100:1 or some other cockamamie ratio. Bearing retainer shatters or melts, ball bearings all end up on one side of the crank, and a huge air leak ensues


IMG_2510.jpeg
 
Usually they don’t seize. If it did, it’s likely from running a dull chain and prying on the dogs all its life and they melted in place. They have plastic bearing retainers to keep the balls in place and those pieces get worn, become brittle and go through the engine eventually becoming melted to the spark arrestor screen.

This is also one of the first things that happens when an oil elitist swears by his “proven” 2 stroke batter at 100:1 or some other cockamamie ratio. Bearing retainer shatters or melts, ball bearings all end up on one side of the crank, and a huge air leak ensues


View attachment 1137139
When a PTO side bearing fails its almost always from some sort of abuse. Especially given low hours as @PV Hiker alluded to.
And yes running less oil than 50:1 is abuse for all those Amsoil zealots.
A fact lost on or not considered by many is that a strato charge saw not only runs hotter, but they also have much less oil going through them.
 
When a PTO side bearing fails its almost always from some sort of abuse. Especially given low hours as @PV Hiker alluded to.
And yes running less oil than 50:1 is abuse for all those Amsoil zealots.
A factlost on or not considered by many is that a strato charge saw not only runs hotter, but they also have much less oil going through them.
32:1 in a strato is about the equivalent of 50:1 in an old school 2 stroke
 
Are bigger crank bearings needed? Some may think so, but often it's not the bearings themselves that contribute to crank failure. It's lack of rigidity in the crank itself. The Suzuki 500 Quadzilla is a great example of this.
The 362 didn't suffer from mass bearing failures that I know off and the 400c has a lighter piston so I'm not sure it's an issue.
The piston weight is about the same from 362 and the 400. The crank isn't. Slipping clutches and dull chains like Kevin said is what likely starts the seal issues. People who crank the chain tight might have gotten away with it on the 361 and 460. I've seen so many smoked 044 pto bearings and rarely an 046/460 or 361 model. The seal will fail but the bearing usually survives. The 044 losses the bearing before seal many times. Almost every 362 brought here was parts, smoked, on the bottom end. They all run 20" bars so it's the purple clutch drum that gives it away. The seals are hard and crunchy to match the bearings. I won't rebuild them. Don't take used burn saws in anymore now. They need a crank most times. Lower rod bearing is also toast most times.
 
Doesn't look over heated to me at all. The "soot" you see above the top ring is normal. My 400C shows the same albeit lighter in color.
It's pretty clear to me that it has foreign object damage of some sort.
I'm going with overheated, pinched rings that forced up the ring and broke the piston. If they don't find bearing cages or chunk of something in there or missing throttle shaft screws it's unlikely it ate something.

Sure would like to see that cylinder and the whole piston. It shouldn't have soot above the rings or below them. Dome or top side definitely carbon and soot there. The fuel normally washes away soot unless it was already running very lean.
 
Hey @huskihl and @bwalker I went out to the shop to look at the old 362 PTO bearing to remember. The cage is all intact and remember that there was something like wood fibers that got into the bearing and seized it up. It did cleanup and spin after getting the foreign particles out. The bearing is definitely not smooth spinning as to why replacing the bearings in the rebuild. The user had money to not mess with mixing fuel and burned Stihl premix. Cheers. Patrick
 
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