576xp broken piston!

[81Bronk36]

So i just got around to removing my muffler and wouldn't you know it you can see the piston in at least 2 peices! So besides the obvious replacement of at least the piston what else should i do while i got this thing tore apart?? Can you port these double strat engines effectively? Is there a big bore kit available? Any advice. Ive never had an 2 stroke broke down this far?

 

[Joe Kidd]

Can you give us some background on your saw? Year model, what you noticed prior to breakage, etc. Sorry to hear that. :msp_ohmy:

Edit: just noticed year model.

 

[mdavlee]

The 576 can be ported for good gains. No big bore kit that i know of. Make sure to rinse the crankcase out when you have the top end off.

 

[Stumpys Customs]

As long as it didn't hurt the port edges or scratch the cyl wall I'd say just a piston, but I have to ask, what caused the piston to break??
I've modded a couple of these one carbed & one auto tune. Here's a link to the AT
http://www.arboristsite.com/chainsaw/204797.htm

 

[81Bronk36]

Thanks for the info guys it was bad old gas. I have only put about 10-12 tanks through it so i didn't use it much kept getting hot and then when it cooled it would restart but then it just shut off. I want to look into a non limiting coil since apparently it's harder to tune the blues.

 

[Stumpys Customs]

Thanks for the info guys it was bad old gas. I have only put about 10-12 tanks through it so i didn't use it much kept getting hot and then when it cooled it would restart but then it just shut off. I want to look into a non limiting coil since apparently it's harder to tune the blues.

I will try to be as polite as possible about this, but you can't tune for bad gas. Nor will an unlimited coil help if you're running old gas. If the gas is questionable toss it. Please don't take this the wrong way. Just trying to help.

 

[tree monkey]

there has to be more to this story.
how can old gas mix break a piston?

 

[Stumpys Customs]

there has to be more to this story.
how can old gas mix break a piston?

opcorn:opcorn:

 

[81Bronk36]

there has to be more to this story.
how can old gas mix break a piston?

Yes you're right i was trying to make my answers short since i am using my phone and it's. A pita.

The other 2 contributing factors were it ran lean and i used stihl oil. I didn't do anything else but run it for several hours like that. I was 4 hours from home and forgot my carb screwdriver. I don't think it would have helped much since i just recently found out you have to tune the blue coils under load.

 

[Roll Tide]

Yes you're right i was trying to make my answers short since i am using my phone and it's. A pita.

The other 2 contributing factors were it ran lean and i used stihl oil. I didn't do anything else but run it for several hours like that. I was 4 hours from home and forgot my carb screwdriver. I don't think it would have helped much since i just recently found out you have to tune the blue coils under load.

Well I can tell you that running stihl oil had nothing to do with any damage. Stihl makes some of the best oil.

 

[Adirondackstihl]

 

[spike60]

What's the serial number?

 

[81Bronk36]

What's the serial number?

09 1800237. I thought it was good oil too but i guess it doesn't have some kind of rating

 

[hamish]

Pistons dont break from old gas or Stihl oil!

D you have a picture of said broken in two piston?

 

[sefh3]

Either I need another beer or we need more to the story.
Stihl oil is one of the best out there.
Bad gas would cause pre-detenation and burn a hole in the top of the piston
but would never break a piston (in 2 pieces).
The limited coil again would not cause this.

How do you know the piston is broke in 2. Post some pictures of this.

 

[81Bronk36]

Either I neView attachment 248858ed another beer or we need more to the story.
Stihl oil is one of the best out there.
Bad gas would cause pre-detenation and burn a hole in the top of the piston
but would never break a piston (in 2 pieces).
The limited coil again would not cause this.

How do you know the piston is broke in 2. Post some pictures of this.

Hope this is the right pic. I took a lot today. The piston has a piece broken off the side. It almost looks like it came from the crank? Its all bent and ripped apart. Then one half of the cylinder wall seams to have stuff on it as opposed to being galled up

 

[hamish]

That is mechanical damage from something being ingested, or a severe overspeed that tossed a bearing.

 

[Stumpys Customs]

My theory, going off of the pic is the piston had excessive wear causing piston slap. If there is to much clearance it will start causing stress fractures and eventually breakage. The ex side of the 576 pistons are not that beefie so I'm not surprised to see it broke like this.

Just my opinion.

 

[RAMROD48]

Hope this is the right pic. I took a lot today. The piston has a piece broken off the side. It almost looks like it came from the crank? Its all bent and ripped apart. Then one half of the cylinder wall seams to have stuff on it as opposed to being galled up

thats called scoring....:hmm3grin2orange::msp_mellow:

 

[dansikes116]

Well I can tell you that running stihl oil had nothing to do with any damage. Stihl makes some of the best oil.

I agree with rolltide, I do not believe the oil had anything to do with it. More than likely the material in the piston had some defects in it. Old gas or new gas, coil, carb adjustment etc made no difference imo!