The wrist pin isn't the problem. A bigger and heavier BB piston doesn't cause this problem, so neither will a slightly heavier wrist pin. I suspect the problem is an out of phase crank.
OEM Stihl pin is also very slightly tapered at the ends to push the circlips down in the groove.
It is lighter than Farmertec, NWP and Meteor pins, a difference of grams not ounces
Is the flywheel set perfectly square on the tapered crankshaft?
This probably wouldn't happen on this model but I have seen a poorly cast captured key cause the flywheel to be seated improperly, vibrated like mad for a second or so till it sheared.
My .02 is on a bad flywheel or crank
I answered this aboveGo ahead, swap out your wrist pin, even install one made of titanium if you want, and then report back.
When you're done with that, explain to us how Stihl uses the same saw for both the MS650 and MS660.
How about the Dolmar 6400, 7300, and 7900. Again, these saws are identical with the exception of a huge variance in topend size.
How about a Stihl 064 with an 066 topend? Or, how about my 440 with a 460 topend turning nearly 16,000 RPMs?
Get the point.yet, or do you need more? Let me guess....
Really?I backed it up. I gave you a link on the wrist pin. I did get the 660 saw running. It was a broken piece of cylinder that caused the problem. I posted all this. You are just looking to cause trouble.
I learned that you in particular are set In His ways and has limited experience with aftermarket parts and you think in terms of OEM parts and the wrist pin is a good example. Or the time you said you did not recommend putting the case in an oven. You are out of your elements in these threads
This is why I respond to you like I do. You repeatedly choose to ignore practical experience and years of building these saws, with both AM and OEM parts, and then either flat out tell us we're wrong, or continue to try and lead others in the wrong direction....your dismissive remarks are incorrect... i guess this indicates your post was wrong about wrist pins and balance.
Careful what you wish for,
How about pie? Apple or cherry would be just fine! Or, how about a mix!
I heard that you already didWell..........I just wanna be able to drop the ban hammer sometimes. lol
I heard that you already did
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