Trusting the Sniff Test...

[Moto Vita]

Not sure if you can see the smoke, but RED LIVES!

Sent from my SM-G930V using Tapatalk

 

[Mat H.]

Ring broke on intake side near the pin.

Unless piston was in backwards.............

Edit: pic on post #1 has piston installed correctly. What does intake port look like?

If that is the case, then it was installed backwards before I got the saw from my dad, and before he got it, because it never failed for him. What makes you think it's backwards?

As far as what the intake port looks like... before or after failure?

 

[HarleyT]

Everyone was assuming that you had been into this saw recently, because that is when these saws usually fark up.
Likely this saw has never been tore down.


As far as what happened to cause it?

**** happens.....

 

[Mat H.]

What’s all back together, the one that broke the ring, or the one in the pic in post#44? New piston? New cylinder? Condition of the bearings in the lower end? Pics of reassembly?

Used head, new piston and rings from Lil Red Barn, new base gasket. Bearings looked good. Fattened the mix up to 30:1 for break-in. Started Red on Sunday and ran great! Started again last night and still ran great. Will run on idle to bursts of half throttle until this tank expires, then back to a 40:1 mix with light duty for that tank. After that, it's back to ripping through trees like a hot knife through butter!

 

[Mat H.]

nice job getting it back together....on original picture I can see a shadow on the rings where it looks like note really fitting the bore to well. Also possibly the ring bottoming in the ring groove "back clearance" could be ring end gap butted together and ring edge jammed on the port breaking the ring.....Looks mechanical and just happened to happen when ya had unmixed fuel.....youll find out soon enough.. Two ring piston could have broke the ring in install and it just broke at a later time...

good luck
the can

I think the shadow is from my hand . Not the best lighting where I was fixing Red. Here is another look from a different angle. For whatever reason, the ring popped out and got itself nice and wedged. Location pins are still in place, so who knows why it tried to jump ship.