MS261 & 026 Pro

[drsamm]

Can anybody tell me positively if the pistons for the 026 Pro and the newer MS261 are the same and will interchange? It appears that both are a rather odd 44.7mm, but I'm not sure about the skirt, wrist pin diameter, etc...or any other differences I can't think of. I can't imagine they would be different, but want to find out before I buy an 026 Pro piston to fix an MS261 I just picked up for $80 bucks...any help/advice much appreciated...

 

[blsnelling]

They are VERY different pistons. The MS261 is a stratified engine, requiring a completely different design of piston. You should be able to get an OEM piston from your dealer for <$50.

 

[drsamm]

10-4, thank you sir. Just the advice I was looking for before making a mistake. Would you happen to know the correct Stihl part number?

 

[Philip Wheelock]

1141 030 2012 for the piston, rings, wrist pin & snap rings. You'll need other parts such as a cylinder base gasket and piston/con rod needle cage. First, though, you have to determine the cause of the piston failure. Cylinder may or may not be serviceable. Air leaks?

 

[drsamm]

Thank you for the numbers...no, I haven't even gotten to take it apart yet. I suspect a bad mix or straight gas. I've been able to clean up about 95% of all the cylinders I've ever found this way. If it isn't too bad, I suspect I'll be able to use it again. Will certainly check for leaks though...good advice.

 

[drsamm]

OK...another piston interchange question, that has nothing to do with the MS261...I got an 028 super for nearly nothing that is near perfect, except for having a bad piston. I also wound up with a plain 034 that a friend let a tree fall against, which broke a hole in the crankcase. The 034 is good for nothing but parts. I believe that both of these are 46mm - please correct me if I'm wrong. Is the 034 piston the same one that is in the 028 super? Both of these are older saws and I can't imagine that even Stihl would make the pistons enough different to not interchange between these two...could one of you guys who answered earlier, please let me know? Would love to put the 028 super back right with what I have on the shelf and get some use out of the 034 basket case.

 

[cutfast]

028 super piston has a pop up or crown on top of it.
034 piston is flat on top so I doubt that they would interchange.

 

[huskihl]

OK...another piston interchange question, that has nothing to do with the MS261...I got an 028 super for nearly nothing that is near perfect, except for having a bad piston. I also wound up with a plain 034 that a friend let a tree fall against, which broke a hole in the crankcase. The 034 is good for nothing but parts. I believe that both of these are 46mm - please correct me if I'm wrong. Is the 034 piston the same one that is in the 028 super? Both of these are older saws and I can't imagine that even Stihl would make the pistons enough different to not interchange between these two...could one of you guys who answered earlier, please let me know? Would love to put the 028 super back right with what I have on the shelf and get some use out of the 034 basket case.

028s is 31x44. 034 is 34x46 bore. Won't work

 

[drsamm]

Of course it won't...thanks for the replies! Now, off to find a new OEM 028S piston kit...