What's wrong with the MS661?

[460 magnum]

I've never had one break like this before

 

[RI Chevy]

It is odd for that saw.

 

[460 magnum]

I know I will be more careful when making a bore cut with a hungry chain.. when the thing failed it also jacked up 4 drive links on that chain

 

[Wilhelm]

Bar/clutch cover nuts not tight enough?
Too much force been resting on the chain tensioner.

That would be my best guess.

 

[huskyboy]

Bar/clutch cover nuts not tight enough?
Too much force been resting on the chain tensioner.

That would be my best guess.

+1 I broke a tensioner on a 394 when the bar nuts loosened and I didn’t catch it in time.

 

[460 magnum]

Bar/clutch cover nuts not tight enough?
Too much force been resting on the chain tensioner.

That would be my best guess.

+1 I broke a tensioner on a 394 when the bar nuts loosened and I didn’t catch it in time.

No on the bar nuts being loose. I know this because I can think back and remember having to loosen them with some pretty good force. Only thing I can account for is making the bore cut the saw made a couple bucks and pop... Maybe even a faulty part from the get go.

 

[andyshine77]

No on the bar nuts being loose. I know this because I can think back and remember having to loosen them with some pretty good force. Only thing I can account for is making the bore cut the saw made a couple bucks and pop... Maybe even a faulty part from the get go.

The amount of force/energy in that type bucking is more than most imagine, if the bar nuts weren't really tightened torqued down good, boom goes the bar tensioner. Think about the momentum of the chain and the power from the rotating assembly, coming to what amounts to a dead stop for a split second. Think of a sledgehammer smacking the tip of the bar. Bore cutting is extremely hard on saws, got to set the depth gauges spot on. I also believe guys bore cut way more than it's needed, seems to be common for loggers in the east for some reason.

 

[Bigmac]

I would say the bar nuts were not tight enough for the force that you had put on it, may have felt tight but must have slid and broke the tensioner, on long bars I tighten the tensioner then the bar nuts then back off the tensioner so there isn’t any load on the tensioner...

 

[Coltont]

Ok got the new chain tensioner in and here's a pic of the one that beikeView attachment 146031 View attachment 146032

I used to do that with 660s. Only took 2 times to figure out what was doing it. You had the rakers to low and a violent chain 1 to many times using the tip to bore. Combined with not having the nuts tight enough. Don't be afraid to crank them tight. Its a saw not a trinket.

 

[RedGas]

I would say the bar nuts were not tight enough for the force that you had put on it, may have felt tight but must have slid and broke the tensioner, on long bars I tighten the tensioner then the bar nuts then back off the tensioner so there isn’t any load on the tensioner...

I never thought about it, but that makes sense. Thanks for the tip.

 

[hseII]

+1 I broke a tensioner on a 394 when the bar nuts loosened and I didn’t catch it in time.

That’s on the 3 series “every fill up check list” Mason.

 

[RI Chevy]

Those saws have small nuts! LMAO

 

[huskyboy]

 

[RI Chevy]

But they run fast and strong!

 

[huskyboy]

Where’s the sensitive members thread?

 

[hseII]

Where’s the sensitive members thread?

Where are you today?

 

[tree monkey]

Where’s the sensitive members thread?

my daddy always said, the best way to take care of a sore dick was don't *f-word with it

 

[huskyboy]

Where are you today?

Cutting encroaching cedar on the right of ways

 

[Semotony]

all the mods add up. just depends on how far down the rabbit hole you wanna go.

Having read the "stroker 661" thread, more than once I had to ask my mechanic why I wood want another heavy, noisy, large ☆ss saw? Told me I was a motor head and wanted to mill faster? Now that I unnerstan where is the line?
I got a "ported" ,they said ,661c, finished the muff mod, maxflowed and began learning how to use this one. Finally got start tips from down in Perth. Fire up, let run a minute, shut down, re-start, play.
When I got the saw the muff can was MT and carbonless, but the cover was stock . Opened up the tight exit hole and that is why a stroked one is wanted. This 1st one is a draught horse, wood like to work with an elephant at the same weight range

 

[Semotony]

Something ate the gear up.

Happens to me every other time I adjust the chain without loosening the bar nuts. Carry extra parts in a tackle box, complete drop in adjuster assembly. Blew up a drive sprocket once on a 460 w/42" bar milling, got a couple o them in there 2 and other stuff