Weird 660 muffler mod

[oneoldbanjo]

I wanted to do a muffler mod that would provide more performance without a bunch of extra noise - and one that would still look reasonably stock. I opened up the holes in the cage in the muffler and added extra ones on the front. In order to enlarge the holes in the bottom I cut a window in the bottom of the muffler, made the holes in the bottom larger and then drilled holes in the plate above the muffler inlet, and then welded the piece from the window I cut in the bottom of the muffler back in. I then removed the spark screen and opened up the hole to allow more flow, and then I welded on an extension to get the exhaust to go forward more so that it doesn't blow exhaust all over the saw. I put the spark screen back into the muffler after I painted it.

The muffler mods increased the no-load rpm by about 1,000 rpm - although some of that may be just proper tuning as I believe the saw was a bit rich as it was only turning 12,300 rpm before the muffler mod. I tuned it to 13,200 and it still sounds a bit rich. I cut up a 30" White Oak over the weekend and it worked great and was not much louder than the stock muffler.

 

[oneoldbanjo]

Here are the photos after the mod.

 

[blsnelling]

Lookin' good Dave! I like to completely remove the baffle, but it's likely not necessary.

 

[Haywire Haywood]

Nice job there with the extended exhaust shroud. Will the spark screen still work?

Ian

 

[RiverRat2]

Nice job there with the extended exhaust shroud. Will the spark screen still work?

Ian

Hey Ian,

From the looks of it I'm betting the spark arrestor stihl works!!!!!

Nice work on the Muffler Mod BTW OOB!!!!! have to rep ya on that exhaust deflector!!!!

 

[blsnelling]

I like that deflector too. I hate the way the case and bar cover get all burnt up on Stihls. I replace the fire screen with sheet metal on my NOS 084. That way I didn't have to mod the muffler body's looks and put the outlets in the cover.

 

[oneoldbanjo]

Glad you like it - I do too! Yes the spark screen still works - I didn't take a picture after I put it back in. I have just finished another one like this for my MS361 - but it is not yet installed. I will post pictures of it in a week or two.

 

[Nitroman]

Stealthy and has a factory look. Good job.

 

[2FatGuys]

That's VERY close to what I just did on my 394XP. I removed the deflector so that I could gut the muffler without having to cut it apart. I removed everything from the inside, through the outlet port, in small pieces, then welded the deflector back in place and extended the deflector. I did have to remove the screen though. Once the deflector is extended on the 394, you can't get to the screw that holds the screen in place. I am still trying to come up with a good way to mount a screen that will remain accessible.

 

[Haywire Haywood]

One question though... why not simply buy a dual port factory cover? I thought that was one of the advantages to the 460/660 muffler. Easy factory muffler mods.

Ian

 

[oneoldbanjo]

I did not want to buy the stock cover as the stock rear portion would still blow the exhaust out on the side of the saw. The exhaust stains the paint near the serial number - and I wanted to avoid that if I could.

 

[Bowtie]

I think it looks awesome! You could still add the dual port if you wanted to, although that may open it up too much...

 

[Haywire Haywood]

I did not want to buy the stock cover as the stock rear portion would still blow the exhaust out on the side of the saw. The exhaust stains the paint near the serial number - and I wanted to avoid that if I could.

Ah, ok.

 

[.aspx]

Why wouldn't you want it louder?

 

[LouieIV]

That nice and clean. I always like clean and stealthy upgrades whether its on a saw or something else.

-LouieIV

 

[maico490]

[/QUOTE]

That's not a weird muffler mod, more like a well cool mod I'd say. Excellent looking job and much more satisfying than just buying a dual port cover and bolting it on.

 

[Bowtie]

That's not a weird muffler mod, more like a well cool mod I'd say. Excellent looking job and much more satisfying than just buying a dual port cover and bolting it on. [/QUOTE]

Right on, I agree. I like the dual port cover on my 064, but I like doing something new and different. To me, a lot of it is the love of doing the modifying. I modded the stock cover for the 064 too...