441 porting questions

[Matt1183]

If Jason doesn't have them I can try to get them Thursday. Just left town for work.

Ok thanks

 

[Matt1183]

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Thanks randy

 

[jmssaws]

I have a build thread on one with numbers but I'm not smart enough to post a link.

 

[paragonbuilder]

View attachment 58155

Hooray OPE!!
The sharing site!!

 

[Mastermind]

Hooray OPE!!
The sharing site!!

Well Dan, as you guys know the "specs" are just a small part of the build. A general rule I've found on most strato saws is to shorten blowdown. Several degrees of crankshaft rotation just move fresh air thru the transfers, so at the risk of making the engine spew more hydrocarbons, you can alter that to make it waste that part of the charge.

Make any sense?

 

[longbowch]

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I don't know if that's what you did to mine, but it runs pretty good.

 

[paragonbuilder]

Well Dan, as you guys know the "specs" are just a small part of the build. A general rule I've found on most strato saws is to shorten blowdown. Several degrees of crankshaft rotation just move fresh air thru the transfers, so at the risk of making the engine spew more hydrocarbons, you can alter that to make it waste that part of the charge.

Make any sense?

Wow! Ok I'm now trying to picture shorter blow down wasting some of the fresh air...
I think I need to take my 261 apart and study it.
And yes, I understand that just telling someone how to do something doesn't mean they can do it like you can...
Way too many aspects.
But still, I'm grateful to be a part of this site, and the amount of willingness to help others learn this art.

 

[Mastermind]

Wow! Ok I'm now trying to picture shorter blow down wasting some of the fresh air...
I think I need to take my 261 apart and study it.
And yes, I understand that just telling someone how to do something doesn't mean they can do it like you can...
Way too many aspects.
But still, I'm grateful to be a part of this site, and the amount of willingness to help others learn this art.

I don't post about saws as much as I once did. I've just done so many that talking saws is like talking about a boring old job. I'd rather post music videos, and shoot the crap. lol

 

[jmssaws]

I use to run more bd in a quad because that's what I heard to do but I've been running less and less and they seem to be stronger but after a while it's impossible to tell what is and isn't.

I know I ported a 7910 a few weeks ago that is the best running saw I've ever ported,not as strong or fast as a 066 94/5 or a 661 obviously but I like the way it runs better than any I've ever done,all saws included.
Over time my style and idea of what a saw needs to be has changed and as of right now it's the perfect saw to me.
I've gotten to where it needs to be strong but also quiet and well mannered and not just fast.
I still like fast saws but when I go to cut a load of wood I'll grab the well behaved and quiet 7910 over the wicked loud ass saw.

 

[CR500]

I use to run more bd in a quad because that's what I heard to do but I've been running less and less and they seem to be stronger but after a while it's impossible to tell what is and isn't.

I know I ported a 7910 a few weeks ago that is the best running saw I've ever ported,not as strong or fast as a 066 94/5 or a 661 obviously but I like the way it runs better than any I've ever done,all saws included.
Over time my style and idea of what a saw needs to be has changed and as of right now it's the perfect saw to me.
I've gotten to where it needs to be strong but also quiet and well mannered and not just fast.
I still like fast saws but when I go to cut a load of wood I'll grab the well behaved and quiet 7910 over the wicked loud ass saw.

You officially have came over to the darkside.....help yourself to some punch and pie.

 

[Chris Zautner]

The stihl ms 441 rcm's are one of my favorite saws to run. I had my stihl ms 441 rcm ported By Alan Wolthuis (aka @awol )
There Are good looking saws too, here's mine

 

[Cigmaker]

The stihl ms 441 rcm's are one of my favorite saws to run. I had my stihl ms 441 rcm ported By Alan Wolthuis (aka @awol )
There Are good looking saws too, here's mine
View attachment 58212

No fair you have extra horse power from stickers lol. It's a dam good looking saw I really like them dawgs.

 

[Cigmaker]

I don't post about saws as much as I once did. I've just done so many that talking saws is like talking about a boring old job. I'd rather post music videos, and shoot the crap. lol

We understand Randy a lot of guys I work with take pictures of crap and share with others. No I'm not joking in the toilet crap a whole new occupation just waiting to be explored. Or a few pictures of cows might be nice eating pie would be better but it's optional.

 

[CR500]

With the 064, the 441 was also very underrated.

I think once ported they are smooth as glass,and have plenty of grunt for a 32" bar being spun by a 7 pin.

Mostly mine wore a 20"&a 28" ES Light

 

[drf256]

I use to run more bd in a quad because that's what I heard to do but I've been running less and less and they seem to be stronger but after a while it's impossible to tell what is and isn't.

I know I ported a 7910 a few weeks ago that is the best running saw I've ever ported,not as strong or fast as a 066 94/5 or a 661 obviously but I like the way it runs better than any I've ever done,all saws included.
Over time my style and idea of what a saw needs to be has changed and as of right now it's the perfect saw to me.
I've gotten to where it needs to be strong but also quiet and well mannered and not just fast.
I still like fast saws but when I go to cut a load of wood I'll grab the well behaved and quiet 7910 over the wicked loud ass saw.

Yup, drivability. Well put and couldn't agree more.

Who cares if if gets through a log a half a second faster? Has to start easily, have a wide powerband, idle well, not be too loud, and overall be balanced.

Given the choice of a 10 second big block '69 Camaro vs a 2017 SS to drive to work, I'd take the 2017 every time. It all has to work together.

 

[drf256]

Well Dan, as you guys know the "specs" are just a small part of the build. A general rule I've found on most strato saws is to shorten blowdown. Several degrees of crankshaft rotation just move fresh air thru the transfers, so at the risk of making the engine spew more hydrocarbons, you can alter that to make it waste that part of the charge.

Make any sense?

I'm still trying to wrap muh head around stratos. Hoping to port my first strato saws this year.

Doesn't whatever fresh vs. mixed charge that remains in the combustion chamber just reach an equilibrium?

In other words, if you could stuff more fresh air in the chamber, wouldn't you just richen the mixed portion to obtain the correct stoichiometric ratio anyway?

 

[paragonbuilder]

I'm still trying to wrap muh head around stratos. Hoping to port my first strato saws this year.

Doesn't whatever fresh vs. mixed charge that remains in the combustion chamber just reach an equilibrium?

In other words, if you could stuff more fresh air in the chamber, wouldn't you just richen the mixed portion to obtain the correct stoichiometric ratio anyway?

I think it's time for me to revist Blair and Jennings. I need to better understand scavenging and how timing effects this. Then try to add these stratos into that theory.

Here is a question. For the purposes of building a strong saw, are stratos beneficial, or are they merely to help emissions, and thus something we work around because they are there?

 

[mdavlee]

The intake is less than 50% of a normal 2 stroke in area. The stratos are feeding fresh air with no fuel in to fill the chamber with the rest. I guess it's burning leaner but closer to the perfect stoichiometric ratio with less wasted fuel out the exhaust.

 

[Mastermind]

Think of it like a layer of pure air sitting on top of the mixed charge coming up thru the transfers. The intention of the designers is to use that fresh air to sweep out the burnt charge from the previous cycle.

 

[drf256]

Then we should need less blowdown? We want to overscavenge intentionally?