Has anyone have a brand new OEM stihl piston explode within seconds of the first start?

[GSully23]

So I'm rebuilding this ms200t....that I just finished building 2 nights ago. I did full rebuild the first time, cases, bearings, seals, and a brand new cylinder and piston kit (everything was OEM) it was evening time and didnt want to bother my neighbors so I didnt attempt to break it in until today. The saw fired up with the choke on, set it to half choke and it fired and went "BOOM ". Couldnt pull it anymore, felt as if in t was locked up, so I then started the tear down. This piston just grenades on itself within the first few seconds of use. I'm currently removing it because I've been dealing with the cylinder which I got extremely lucky to salvage with almost no damage.....and I even have a compression test picture before this happened reading slightly over 150psi. And yes i used assembly line and everything.

Luckily i purchased a meteaor piston before finding out you cant just buy an OEM 200t cylinder alone and now I have a back up to install. But it does make me question some of stihls OEM parts just like the bakelite crank seals they use. After ruining one set installing I ordered another set of OEM and aftermarket seals and the aftermarket seals deffinitely appear to be of a much better quality/styleView attachment 686177

 

[GSully23]

Heres another shot removed....I just dont understand it. I washed the new cylinder with soapy water to remove any leftover stuff. The compression check and functioning was fine until it ran for more than a few seconds.now I have to go back and make sure the cranks still true and everything.....call me a cry baby but stuff like this sucks when you invest the money into these saws to keep them original. Also found the bra d new fuel/vent line is a little longer than the original so I have to find a way to re-route it so it will vent properly. And every part is OEM like I stated before

 

[HarleyT]

Sounds like you did something "very" wrong!!!!

 

[HarleyT]

Like didn't notice the bearing coming apart?

 

[HarleyT]

Or leaving your car keys in there!!!

 

[HarleyT]

Throttle plate screw?

 

[HarleyT]

Many builders here like to blame Stihl for their failures......

 

[HarleyT]

Yes, the vent line!!!

 

[HarleyT]

Sorry, just teasing you a bit...

 

[lone wolf]

So I'm rebuilding this ms200t....that I just finished building 2 nights ago. I did full rebuild the first time, cases, bearings, seals, and a brand new cylinder and piston kit (everything was OEM) it was evening time and didnt want to bother my neighbors so I didnt attempt to break it in until today. The saw fired up with the choke on, set it to half choke and it fired and went "BOOM ". Couldnt pull it anymore, felt as if in t was locked up, so I then started the tear down. This piston just grenades on itself within the first few seconds of use. I'm currently removing it because I've been dealing with the cylinder which I got extremely lucky to salvage with almost no damage.....and I even have a compression test picture before this happened reading slightly over 150psi. And yes i used assembly line and everything.

Luckily i purchased a meteaor piston before finding out you cant just buy an OEM 200t cylinder alone and now I have a back up to install. But it does make me question some of stihls OEM parts just like the bakelite crank seals they use. After ruining one set installing I ordered another set of OEM and aftermarket seals and the aftermarket seals deffinitely appear to be of a much better quality/styleView attachment 686177

OEM Stihl parts are the best for that saw that you can get.The aftermarket seals are not better you just think they are because you broke the OEM seals putting them in improperly. How did you get the flywheel and clutch on that saw with a piston stop by chance? I'm wondering if that broke it?

 

[HarleyT]

We used to have to endure many posts about some members destroying their saws, and blaming Stihl or whoever. So I get a tad touchy....
Your piston has hit something serious, and the one who rebuilt the saw is to blame.

 

[HarleyT]

Or we could chase some internet rabbits for a few weeks.

 

[lone wolf]

We used to have to endure many posts about some members destroying their saws, and blaming Stihl or whoever. So I get a tad touchy....
Your piston has hit something serious, and the one who rebuilt the saw is to blame.

Thats what it seems like .

 

[HarleyT]

What did it hit?

 

[HarleyT]

With luck, the site owners will fix their site problems.

 

[HarleyT]

Or at least the duplicate posts will be removed...

 

[TBS]

Looks like it ate a bearing.

 

[GSully23]

Wow....really surprised you guys are taking it this far out of context. I still have a set of the OEM seals sitting here, but I chose not to use them. No, I did not eat a bearing, they are all brand new. I was simply asking if this has ever happened to someone. The only thing I can think of is an issue with the cylinder walls, I did not inspect them that closely because it was new. I will include a picture of where the contact was made. I am a certified Yamaha outboard technician, which has nothing do do with chainsaws but I have been working on engines for almost 18+ years. Unlike many people I am a die hard stihl fan. You all have twisted this "question" in a very different direction. I was legitimately asking a serious question.....what do you think would have caused this?

I've never seen any of you all jump at someone's throat so quick.....but damn, so.something happened and I myself cant tell

 

[HarleyT]

Obviously it is a chunk of something real hard that got sucked up into an intake port.

 

[HarleyT]

So it was sucked into the intake or down in the crankcase.......