Stihl MS650 -- broken -- rebuild?

When fins are broken on intake side its not as risky as on outlet side.
This one I would run without much thought..

Had many saws I run with broken fins.

Cooling is better on intake side as all air pass this. Left side and muffler side is is hottest
Partner had an idea about combining fluid cooling and air cooling. Fluid around cylinder to absorb and transfer heat evenly.
A more effective cooling and this would keep temps in better levels. Sadly, this never got off drawing table.
 
Here's another thing about most dealers .Nothing derogatory intended but they will quote pretty much to company policy weather a saw needs certain repairs to adhere to factory specifications .Those may or may not fit in every situation but that's how they are trained .Problem is in many cases being the repairs might exceed the value of the saw .
 
Too bad about the boo-boo, but I'm with the rest of the crowd here. Run it.

Do you have the broken pieces of the fins still? If so, for humor you might try JB Weld to re-attach them. If you make sure you have a very clean mating surface and a tight fit, it might take, and although it probably won't transfer heat as well as before, it might do better than no fins :).

I might try that just to make myself feel like I did something...if not, it'll almost surely be fine just as it is.
 
I was thinking tig welding the fins or making new ones to attach if it was a concern. You wouldn't have to butt the pieces, just lay them on top of the broken fins, then spark and tack.
 
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  • #34
I might try that just to make myself feel like I did something...if not, it'll almost surely be fine just as it is.

hahaha...I can SO identify with that approach. At least try something...:lol:

Jay...I know the words...tig...mig...for welding but they are just words. My speed is JB Weld.:D
 
There is sticks for arc welders as well if you know what material it is.
That is the trixy part... Material and how it will react to heat.

I gave up on all that guessing and testing and just glue them.

If its just air flow you are after its not so hard. A bit worse if you want the fin's to radiate heat as well.
 
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  • #37
Ha! Good question...I had forgotten this thread. Yes...we used it on a big pine, Irma related, about 3 weeks ago. It did just fine.

We had the shop just replace what was necessary and are running it with broken fins, no problems so far.

We just bid on an $8300 storm job...big hickory on a building and a big oak leaning over the same building. The 650 will get some serious use if we get that job...I'll let you know how it does with sustained running.
 
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