Muffler mod advise, EA4300 Makita

[Ford3000]

I don’t like the heat the cat retains in the muffler,
So I drilled out the two tacks of weld holding the housing the cat is attached to,
I then cut the cat out and tidied up the hole this left.

All I want to do is make the the saw run a bit cooler, will the removal
of the cat play a big enough part in keeping the heat down,
I have no tools to cut the baffles just behind the outlet screen, so am hoping
I have done enough, I could do away with the complete section the cat was welded to,
but am afraid that would result in one hell of a noise increase.

Your advise is welcome, and thanks.

 

[Mkinslow]

I'm not familiar with this model, but I did my ps421 before I sold it and all I did was remove the cat but didn't open up the outlet,helped a lot and didn't really get any louder. You most likely have to retune your carb settings though

Sent from my SM-G892A using Tapatalk

 

[Ford3000]

Thanks @Mkinslow
If I understand you, you only removed the offending
round cat, like in the image below.
Your saw is the same as mine, just the colour differs.

Did you remove the spark screen, had you to retune.

 

[NPKenny]

@Ford3000

I did exactly what you did and was happy with the results. My saw already had in the neighborhood of 0.020" squish and ran very well. Removing the catalytic converter and cleaning the remaining outlet was very helpful for temperature, throttle response, etc. Its a very quiet saw, with a tolerable tone.

 

[Mkinslow]

Thanks @Mkinslow
If I understand you, you only removed the offending
round cat, like in the image below.
Your saw is the same as mine, just the colour differs.

Did you remove the spark screen, had you to retune.

Yes sir that's exactly what I did, I did have to retune the carb also

Sent from my SM-G892A using Tapatalk

 

[Ford3000]

@Ford3000

I did exactly what you did and was happy with the results. My saw already had in the neighborhood of 0.020" squish and ran very well. Removing the catalytic converter and cleaning the remaining outlet was very helpful for temperature, throttle response, etc. Its a very quiet saw, with a tolerable tone.

Thanks @NPKenny
I will assemble and fit in the morning, this saw already has a snappy
pickup, Hope I don’t manage to mess that up tuning it, I know it will
need a bit more on the high jet, not sure till I start her up again what
the low will be like, it didn’t pick up for 20 seconds after a cold start,
but sure jumped to attention then, had a nice clean burn with a nice
oily shine visible when I looked in the exhaust port, even after sitting
a month.

Any harm in asking what your mix ratio is, thanks

 

[Wood Chopper]

Thanks @Mkinslow
If I understand you, you only removed the offending
round cat, like in the image below.
Your saw is the same as mine, just the colour differs.

Did you remove the spark screen, had you to retune.

My 4300 responded nicely to it. You can leave that entire piece on the right out. Some people pry the fins on the front open a little more... I didn't but yes I love the saw.

 

[Ford3000]

My 4300 responded nicely to it. You can leave that entire piece on the right out. Some people pry the fins on the front open a little more... I didn't but yes I love the saw.

Thanks @Wood Chopper
If your happy with yours am sure I will be with mine.
Did you leave the piece on the right out or just do same
as am trying.
I have Two of these so will see how this one works out
before I do the other.

 

[Ford3000]

Anyone put a tach on these, what would you run at, not even
broken mine in yet.

 

[Wood Chopper]

Thanks @Wood Chopper
If your happy with yours am sure I will be with mine.
Did you leave the piece on the right out or just do same
as am trying.
I have Two of these so will see how this one works out
before I do the other.

Leave it right out my friend

Anyone put a tach on these, what would you run at, not even
broken mine in yet.

Limited coil so that is tricky. I was given the advice to start rich and lean it out till it's just hitting the limiter on the tach (tach will start going haywire with numbers) and then go a bit more is a good to start.

 

[full chizel]

After i did the 421 i had it ran best about 13,200ish RPM

 

[Simondo]

Start point.....

.......then keep the bottom 2 parts . Flat screw driver is a easy way to open up the gill slits for more flow without grinding anything.

 

[Ford3000]

Hi @full chizel
Did you remove the cat or the cat and the housing it’s welded to.
I removed the cat from one saw, ran it on 40:1 Mobil 1 and it is a ripper,
she is at 13200 and sounds great.

Then I did as @Wood Chopper mentioned and removed the cat
and the plate it’s welded to, that saw needs too much fuel to get
it to 4 stroke, I have it tached at 13000 to get it to 4 stroke.
Not sure if I will keep it this way as it’s a little less sharp from
the off than the other one, even though I gave it a small amount out on the
low to help this, this brought the idle down ever so slightly too as it had climbed
a smidge after the muffler work, gave it a slight out on the H side too.
I can get it to 13200 by putting in the H again though, but it doesn’t 4 stroke much,
The plug tells me am definitely not lean either.
Anyone care to comment on which way to proceed to get this second saw to 4 stroke at 13200,
it initially went to 13600 after the mod, so I cut it back to 1300 to get it stroking,
I think the muffler over all sounds different than the first modded one with that third plate
still in place.


I have a feeling it won’t get to be as snappy as the one with just the cat removed, there’s
a lot less back pressure which has me thinking that’s the reason am at 13000 to get the
saw stroking, while the other identical saw will even stroke at 13500 if I want that.

 

[Ford3000]

Start point.....
View attachment 222265
.......then keep the bottom 2 parts . Flat screw driver is a easy way to open up the gill slits for more flow without grinding anything.

View attachment 222266

Hi @Simondo
I have done one muffler with the two pieces and one
with just the cat removed, so far the one with only the cat removed is
the zippiest, four strokes well too at 13200, the muffler put back with just the Two front pieces is not as snappy, I had to set it to 13000 with the tach to
get it to 4 stroke, and take out the low a shadow to sharpen up the response.
Am I doing something wrong as the first identical saw with only the cat cut out
seems to have turned out the best of the two, the second one does run cooler though.

 

[full chizel]

Hi @full chizel
Did you remove the cat or the cat and the housing it’s welded to.
I removed the cat from one saw, ran it on 40:1 Mobil 1 and it is a ripper,
she is at 13200 and sounds great.

Then I did as @Wood Chopper mentioned and removed the cat
and the plate it’s welded to, that saw needs too much fuel to get
it to 4 stroke, I have it tached at 13000 to get it to 4 stroke.
Not sure if I will keep it this way as it’s a little less sharp from
the off than the other one, even though I gave it a small amount out on the
low to help this, this brought the idle down ever so slightly too as it had climbed
a smidge after the muffler work, gave it a slight out on the H side too.
I can get it to 13200 by putting in the H again though.
The plug tells me am definitely not lean.
Anyone care to comment on which way to proceed to get this second saw to 4 stroke at 13200.

I have a feeling it won’t get to be as sharp as the one with just the cat removed.

I removed to whole plate the CAT was attached to.

 

[Ford3000]

I removed to whole plate the CAT was attached to.

Hi @full chizel
thats what I did too, after which the saw tached out at 13600, so I brought it
down to 13000 on the tach to hear some four stroking, if I go to 13200 the 4 stroking is faint.
Would it be safe to use the tach and set up to 13200, the saw looks a tad rich according to the plug.

 

[full chizel]

A faint 4 stroke is what you want. You want it to clean up as soon as it touches the wood. Between 13k-13.5k is gonna be fine i just found 13200 was the sweet spot on mine but every saw will be different. Reading the plug isn’t real accurate its best to listen to the tune.

 

[Ford3000]

A faint 4 stroke is what you want. You want it to clean up as soon as it touches the wood. Between 13k-13.5k is gonna be fine i just found 13200 was the sweet spot on mine but every saw will be different. Reading the plug isn’t real accurate its best to listen to the tune.

Thanks @full chizel
I think I will leave this saw at 13000 and tune a little out of it in the Wood,
its not far away, honestly think it’s the slight drop in back pressure that is
causing me to need more fuel to make her four stroke,

13200 is very pokey and pleasing to the ear on this saws twin, neither are broken in yet so some small adjustments will suffice.

 

[full chizel]

Thanks @full chizel
I think I will leave this saw at 13000 and tune a little out of it in the Wood,
its not far away, honestly think it’s the slight drop in back pressure that is
causing me to need more fuel to make her four stroke,

13200 is very pokey and pleasing to the ear on this saws twin, neither are broken in yet so some small adjustments will suffice.

It’s always better to be a little rich than lean

 

[Simondo]

Hi @Simondo
I have done one muffler with the two pieces and one
with just the cat removed, so far the one with only the cat removed is
the zippiest, four strokes well too at 13200, the muffler put back with just the Two front pieces is not as snappy, I had to set it to 13000 with the tach to
get it to 4 stroke, and take out the low a shadow to sharpen up the response.
Am I doing something wrong as the first identical saw with only the cat cut out
seems to have turned out the best of the two, the second one does run cooler though.

Iv never done one without doing a full cat and mount removal as it takes very little time just to drill the 2 spot-welds and pop out the hole unit as one.
13000 rpm is the number I end up with as well...much after that the tac starts to jump around so I don't push for a leaner mix. I never grind out the gills but just straighten up the slots to give more flow and to keep a stock look without to much extra noise. I set each saw from basic settings , then....As long as the saw drops back to idle smartly with no cycling and picks up smartly from idle....hits 13000 free RPM with a slight 4 stroking and then , without the need to push much in a cut to take it out of any 4 stroking ....Im good ,if not ... I adjust L & H accordingly.