RedMax/Earthquake/Ryobi/McCulloch Muffler Mod

Chris-PA · Feb 3, 2013

I decided to do a better muffler mod for the Earthquake CS3816 as I didn't like the one I'd done first. That one I just drilled holes through to the back chamber from the outlet area, which certainly works but it louder than it needs to be. Also, the Earthquake muffler was a cat muffler and since I left the cat material in there it still gets hot in spite of being bypassed. I liked the method I used on the McCulloch MS4018, which was to make an access hole in the muffler body and then make a cover to block off the hole. This time I figured I go in from the back (be quiet you, I heard that!). Sorry for the crappy phone pictures.

I started with a Ryobi muffler I got off of eBay:

First I modified the outlet area by drilling it with a 3/8" bit and then grinding it open with a die grinder. Note that I did not go all the way through the middle baffle:

Chris-PA · Feb 3, 2013

Then I drilled in from the back, and through the middle baffle. There are two very small holes there already - they look to be less than 1/4". I also cut a small plate out of a stainless cover from an old microwave oven:

Then I stuck the die grinder in there and hogged open the middle baffle as best I could. I enlarged it into the two holes that were already there, making a rather irregular opening, but it has a decent area. This shot is looking in through the muffler inlet port - hope you can see:

This is with the cover installed after a bit of shaping work with an 8oz rubber mallet:

I sealed the cover with Permatex Ultra Copper. This is the same basic muffler that is used on all these RedMax based saws, so it would work on any of them. I have to put it on yet, but I got cold in the barn.

BrocLuno · Feb 3, 2013

Looks good !!

Chris-PA · Feb 3, 2013

Seems to run well. I would not say it is quiet, but it does not have as much high frequency stuff so it is not as annoying to listen too.

Chris-PA · Feb 3, 2013

BrocLuno said:
Looks good !!

Thanks!

o8f150 · Feb 3, 2013

once you put it all back together you would never know it was opened up until you start it

View attachment 277192 View attachment 277193

Chris-PA · Feb 3, 2013

o8f150 said:
once you put it all back together you would never know it was opened up until you start it

View attachment 277192 View attachment 277193

Yes, I did one like that:

But as I said the catalyst still got hot and it was louder than I wanted. This one should flow fine and it is quieter and cooler.

Interestingly, whatever the muffler characteristics I noticed that with this one, like the similar one I did for the McCulloch MS4018, it is very hard to hear the 4-stroking. With the wide open one above it was not hard to hear. It's not that quiet - just tolerable without ear protection - but the misfire is not distinct. I had thought that might be due to the MS4018 being strato, but it appears to be due to the muffler. The exhaust takes a fairly long path to get out.

PJF1313 · Feb 3, 2013

.

Boy, ya'll a bunch a lazy SOB's!! :hmm3grin2orange:

The ones I've done, 2x 38's and one of each 41 and 45's, I took a Burns-O-Matic (sp?) to the seam and split it with a screw-bar. Used a Dremel with a cut-off bit to :

Hack off the fist baffle (Cylinder side) - 3 spot welds

Mutilate the Cat (mid baffle) tougher than it seemed at first, but learned to cut along the indented area and made a rectangle of out a round :laugh:

Opened the outlet to a smidgen under the EXTERIOR deflector - There is also ANOTHER interior deflector that get mostly wacked with the exterior mod.

Sorry, no pics YET, but I still have a couple of 38's nib @ work. Just waiting for them to kill the first one (damn - gota take pics of that also)

Chris-PA · Feb 3, 2013

I didn't really want to pry it apart. I knew I could make a decent cover plate and not have it be all buggered up. I suppose I could practice that on the cat muffler now that I have this one done.

dboyd351 · Feb 10, 2013

WHW,
This is modding a Ryobi 10532 muffler, so this mod could also be used on the Redmax 400/4000 and Ryobi 10532 saws, right?
How much louder than stock would you say it is?
Thanks

Chris-PA · Feb 10, 2013

And the RedMax G3800 and small Earthquakes and apparently some MTD branded Jenn Feng saws too. A lot of these RedMax saws got sold as other brands.

Anyway, it's tough to say about the sound level - it can be pretty subjective without a sound level meter which I surely don't have! I did this one for a 38cc Earthquake and I was running it today. At first I ran it with my ear protectors on, which I almost always wear anyway, but then I took them off for a while and I did not find it objectionable. I never ran the Earthquake stock, and I did a similar mod to this on my MS4018 (GZ400/4000) some time ago so I can't really compare it to that stock either. It is certainly quieter than the first Earthquake muffler mod, which was pretty much wide open and really loud.

As I said upthread, both this muffler and the one on the MS4018 make it hard to hear the 4-stroking, while that was not the case with the first wide-open Earthquake muffler. I believe that is a sign that it is reducing the sharp, high frequency sounds and making the misfire less distinct. That's probably as close to quantifying it as I can get.

JeffandTamara · Dec 1, 2013

Chris-PA said:
And the RedMax G3800 and small Earthquakes and apparently some MTD branded Jenn Feng saws too. A lot of these RedMax saws got sold as other brands.

Anyway, it's tough to say about the sound level - it can be pretty subjective without a sound level meter which I surely don't have! I did this one for a 38cc Earthquake and I was running it today. At first I ran it with my ear protectors on, which I almost always wear anyway, but then I took them off for a while and I did not find it objectionable. I never ran the Earthquake stock, and I did a similar mod to this on my MS4018 (GZ400/4000) some time ago so I can't really compare it to that stock either. It is certainly quieter than the first Earthquake muffler mod, which was pretty much wide open and really loud.

As I said upthread, both this muffler and the one on the MS4018 make it hard to hear the 4-stroking, while that was not the case with the first wide-open Earthquake muffler. I believe that is a sign that it is reducing the sharp, high frequency sounds and making the misfire less distinct. That's probably as close to quantifying it as I can get.

JeffandTamara · Dec 1, 2013

I recently got a Ryobi C4620. I took the Muffler off to see if there is a screen blocked or something, None that I could see...I twisted off the bolts when I went to take it off, so now, I gotta find some more bolts... Is there a Really Simple Muffler Mod that might give a little more umph.., I am talking something with no welding.... This post said there is a Catalytic converter in the muffler...I guess that is probably hard to get to as well... I don't want to tear up more than I already have...

trophyhunter · Dec 1, 2013

You can drill from the inlet hole in the back of the muffler and right through the cat and out the front side for a down and dirty muffler mod. It really wakes up the 45cc Redmax clones were messing around with in the Earthquake saw thread. You'll be shaking the shavings and mess out of the muffler for a bit but it makes a huge difference.

Don't be afraid to get a torch head and a bottle of MAPP gas and pry open one of them on the middle seams. You can effectively gut the whole muffler if you open it up this way, and all you really have to do is peen the seams back over and flat and your muffler is back in business, no welding or brazing needed. You'll still want to add another hole in the front cover or modify the existing hole and screen to make it bigger.

JeffandTamara · Dec 2, 2013

Thank you so much!!! I have ordered some new bolts that I twisted off getting the muffler off... I think I will go with the drill through the exhaust inlet first and evaluate. How big of an opening would you start out with? The place I ordered the bolts through indicated the Muffler is no longer available?? If I can locate another muffler...I might try to open it up.
Is there any downside to doing these mod's, other than perhaps needing to adjust the Carb...Would the engine run hotter?,,, I wouldn't think so... Or is the louder noise the only downside?
I remember years ago, I traded for a Kawasaki Triple 2- stroke bike. The guy I bought it from just couldn't get it to make any power...It would rev right up with out a load, but it was a dog going down the road. I went through the carbs, and added individual breathers, still no luck, but for some reason I decided to pull out the muffler baffles...They were plugged nearly solid....Took a wire brush to them and put them back in, and I had a screamer!!! Those were the days way before the internet where you can get more ideas about things than just your own!!! Thanks again.

trophyhunter · Dec 2, 2013

No, your engine is going to run much cooler for three main reasons. One, your allowing the rate and volume of exhaust emissions to make it's way out of the saw faster.

Two, eliminating the catalytic converter just by itself if you did no other mods would make a huge decrease in temperatures on the exhaust side of the P&C.

Three, by allowing more area to flow exhaust out of the saw you can now open the high side carb adjustment up and increase the fuel mix flow, that is going to make more power and run cooler by eliminating the lean operating condition that existed with the restrictions.

dboyd351 · Dec 2, 2013

JeffandTamara said:
I remember years ago, I traded for a Kawasaki Triple 2- stroke bike. The guy I bought it from just couldn't get it to make any power...It would rev right up with out a load, but it was a dog going down the road. I went through the carbs, and added individual breathers, still no luck, but for some reason I decided to pull out the muffler baffles...They were plugged nearly solid....Took a wire brush to them and put them back in, and I had a screamer!!!

Those Kaw triples were screamers. Didn't handle as well as some bikes, but they were wicked fast in a straight line.

trophyhunter · Dec 2, 2013

JeffandTamara said:
I recently got a Ryobi C4620. I took the Muffler off to see if there is a screen blocked or something, None that I could see...I twisted off the bolts when I went to take it off, so now, I gotta find some more bolts... Is there a Really Simple Muffler Mod that might give a little more umph.., I am talking something with no welding.... This post said there is a Catalytic converter in the muffler...I guess that is probably hard to get to as well... I don't want to tear up more than I already have...

If you go to the Earthquake saw thread, I did another muffler mod today and took pics and posted them.

RedMax/Earthquake/Ryobi/McCulloch Muffler Mod

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