Aftermarket Dual Port Muffler for Stihl 064AV

[IH3444]

I have an almost new Stihl 064AV saw which I bought at a dealer liquidation sale back in 1995 for $600. I have purchased the upgraded larger HD2 air filter OEM parts and am going to install those. I was thinking of it needing possibly also a more open better breathing exhaust system other than the stock single opening one it has now. The muffler has the welded-on safety grill from the factory, so I was thinking of purchasing one of these dual port mufflers off of ebay. The saw has maybe 30 hours on it and is an absolute beast of a powerful saw. Just started it up after 8 years of sitting, unbelievable. All the talk about the 500i made me think of getting this saw back into shape. During a large 130-foot red oak tree blow down cleanup my O36 PRO muffler modded retuned saw just stopped working. That turned out to be just a carb cleaning, and everything was back to normal. During that problem I just swapped the 20-inch bar to the 064, and WOW, what a wood cutting machine that was. If you could take a look and comment if this muffler is worth purchasing. I know I have to retune the saw after. Thanks for your interest and comments. Right now using the MS661 Magnum for all the heavy lifting.
https://www.ebay.com/itm/1547196513...oLw/hxM7l9WmBI2mQ9wMAHf/rABy|tkp:BFBM3NGt4I9j

 

[grizz55chev]

I have an almost new Stihl 064AV saw which I bought at a dealer liquidation sale back in 1995 for $600. I have purchased the upgraded larger HD2 air filter OEM parts and am going to install those. I was thinking of it needing possibly also a more open better breathing exhaust system other than the stock single opening one it has now. The muffler has the welded-on safety grill from the factory, so I was thinking of purchasing one of these dual port mufflers off of ebay. The saw has maybe 30 hours on it and is an absolute beast of a powerful saw. Just started it up after 8 years of sitting, unbelievable. All the talk about the 500i made me think of getting this saw back into shape. During a large 130-foot red oak tree blow down cleanup my O36 PRO muffler modded retuned saw just stopped working. That turned out to be just a carb cleaning, and everything was back to normal. During that problem I just swapped the 20-inch bar to the 064, and WOW, what a wood cutting machine that was. If you could take a look and comment if this muffler is worth purchasing. I know I have to retune the saw after. Thanks for your interest and comments. Right now using the MS661 Magnum for all the heavy lifting.
https://www.ebay.com/itm/1547196513...oLw/hxM7l9WmBI2mQ9wMAHf/rABy|tkp:BFBM3NGt4I9j

Be aware that this does not have a spark screen, might not be a problem in your area, but around here in Northern Cali,that's a no go due to high fire danger.

 

[Bob Hedgecutter]

In my own experience- the aftermarket front plays nice with the aftermarket back- but not so good with the OEM back.
Often the mounting holes are up to half a hole out if alignment and the flanged edge is either larger or not the exact same shape as the OEM rear section- that require mechanical fitting and material removal.

I have not tried for a while- but over here we could still get the OEM dual port mufflers and/or the dual port front replacement section. That is what is on my 066, my 064 and MS460.

 

[Bob Hedgecutter]

 

[Woodslasher]

I 2nd what Bob said, that port on the front cover doesn't look big enough to do ****. Get a real dp outer cover (oe or a/m, doesn't make a difference) and that'll really help the saw.

 

[IH3444]

Thanks for the replies and pictures.

 

[trains]

if your going to go aftermarket, get something like this.

https://www.ebay.com/itm/2850378279...KtWEcoK9e0fQPFc5VFR9BVufEg==|tkp:BFBM1rWTl5Bj
but as has already been mentioned, the fitment is not always that good, if it was my saw, I would just get a gen one from the stihl nearest or best service for you, and pay once, cry once, then enjoy it.

 

[thompsoncustom]

those mufflers in your link work good after you cut out the baffle and open up the holes on the front and back cover some.

 

[IH3444]

Thompson, if you are speaking of the link I posted, that is what I am thinking. I did that to my OEM Muffler for my Stihl O36 Pro, and it did wake it up a good bit. Thanks!

 

[NSEric]

I'd just make the factory outlet bigger or add a deflector to the flywheel side on the side of the muffler, I wouldnt put a hole in the front cover or buy a front cover with a hole in it.
The 660 clones come with the front cover that's in the the first post. On mine I ground the hole in it out big enough for a 1 inch pipe, it's good and loud now.
If I had a do over, I'd weld up the little hole in the front cover and add my 1 inch pipe to the flywheel side as far back as I could get it. Having the exhaust opening close to the rear makes the saw quieter then having a hole in the front cover.

 

[Bob Hedgecutter]

If the saw is near new and pretty pristine- I would not hack into the original muffler or do anything that is going to alter it beyond reversible repair.
If you want to do a hack and weld- do it to a copycat after market muffler- or get a genuine dual port front for the factory muffler.
The old dear deserves it if it has lasted this long in still great condition.

 

[Lightning Performance]

I swapped on a bunch of Highway covers recently to 660s and no issues with the fitment

 

[Bob Hedgecutter]

I swapped on a bunch of Highway covers recently to 660s and no issues with the fitment

not tried Hyway ones yet- not really available here, my comment was more aimed at the aliexpress and Farmertec types that I have seen personally- like most copy stuff, some works and some doesn't work exact- it all comes down to no real quality control.

 

[Lightning Performance]

not tried Hyway ones yet- not really available here, my comment was more aimed at the aliexpress and Farmertec types tat I have seen personally- like most copy stuff, some works and some doesn't work exact- it all comes down to no real quality control.

I just bought two of the Dual Port farmer Tech mufflers I was surprised they had a full rear plate in them now. The muffler's cheap. The front louver you need about three of them to make it breathe and the back section basically is a clone of the OEM now. I'll have to try some cover swaps. I have the Canadian dual Port Factory OEM Stihl front covers here. I have Highway and now this FT trash. They are going to be butched for a header pipe insert.

 

[Dennisthemenace]

As mentioned by others, if you have a 064 in near pristine condition it deserves only genuine Stihl parts.
They don't make em like that these days

 

[IH3444]

Thanks for the ideas, and comments. I do want to keep the original muffler unmolested. So that's why I'm buying an aftermarket one to modify.
Found the Farmertec one, thanks LP!
https://www.farmertec.com/Exhaust-M...MS650-064-Chainsaw-1122-140-0604-p228291.html

 

[IH3444]

So should I just clear out all the internal baffling inside the Farmertec one I received?

 

[Lightning Performance]

So should I just clear out all the internal baffling inside the Farmertec one I received?

You bought one with baffles, and AM, eww. All my AM ones were hollow but the Hyway housings so I stopped buying those. They do have a better rear support internally for work tools going logging.

Yes, gut the cage, all of it but leave the stamped plate. Many drill the spot welds. They usually crack, leak or both. Leave the backing plate is best.

 

[IH3444]

Got the Farmer Tech one completely gutted and enlarged the side port with an 0.800 internal diameter pipe coming off where the original exhaust was. I did my 036 pro exactly like this and was pleasantly pleased with the results. Although both are not at the recommended 80%, I feel a bit of back pressure is good. I was going to purchase a new non oem exhaust gasket off ebay. I see that they are from China. Are these good or OK quality?