MS661C Muffler Mod Testing

[Chainsaw Jim]

What purpose does a 20 inch bar serve on a 90cc class saw? Just curious.

I recently picked up a 661 and it doesn't cut any faster than my 362 until it's buried in bigger wood.

661 36 inch bar
362 28 inch bar

Well then throw a 9 tooth sprocket on the 661 and see how that statement holds. Lol hang on tight.

 

[KG441c]

My internal frequency monitoring device told me

You might have been hearing the ringing in your ears Brad from all the extra noise?? Lol

 

[blsnelling]

Bump for those modding the muffler on their 661.

 

[HarleyT]

 

[Cody]

Bump for those modding the muffler on their 661.

Have you been able to do much more testing with a longer bar? I've just opened up the factory opening, screen in and it's was a big difference. Would removing the baffle decrease torque at all? I've read it all at some point in time but can't remember what was what. I rarely use that saw, just wanted to open it up to let it breath and lower temps.

 

[ferris076]

Remove the baffel

 

[blsnelling]

These saws don't need back pressure. Remove the baffle.

 

[Stihlofadeal64]

These saws don't need back pressure. Remove the baffle.

It is baffling to me that they even put the baffle into the muffler. But I'm baffled by many things that engineers do at times.
The other baffling thing is that those of us with basic small engine skills can't understand placing the baffles into the mufflers.
All this is simply baffling!

 

[blsnelling]

You're baffling me!

 

[blsnelling]

Would removing the baffle decrease torque at all?

No.

 

[Cody]

No.

I ended up catching another thread of yours where you flat stated removing the baffle was the best option, maybe I'll sit down this weekend and do that! I do have a few stumps to cut flush to the ground which I'll be using that for, thanks for the response.

 

[jmssaws]

Not trying to argue but on a work saw I leave the baffle in because they have a habit of breaking at the flange once removed.
They run just fine with it in there,I ported this one today,the baffle is intact.

 

[jmssaws]

What purpose does a 20 inch bar serve on a 90cc class saw? Just curious.

I recently picked up a 661 and it doesn't cut any faster than my 362 until it's buried in bigger wood.

661 36 inch bar
362 28 inch bar

You either have a stud 362 or a dud 661.
Maybe both.
There both limited in rpm so with the same bar and chain and sprocket how could a 91cc saw not be faster than a 59cc one with any bar?

 

[blsnelling]

...they have a habit of breaking at the flange once removed.

There are multiple layers of heavy gauge stainless steel even without the baffle.

 

[jmssaws]

There are multiple layers of heavy gauge stainless steel even without the baffle.

Yep and they break at the flange same as a 1122 muffler.

 

[661Joe]

So if i buy a brand new ms 661 then completly gut the muffler.. ill gain a noticeable amount of grunt with no ill effects. Thanks Joe