Modify Saw Muffler .... is It Worth It or Not and How To Do It ? ? ?

[H60 Hawk Pilot]

I Just did a Search and Noticed Different Ideas.

I have a couple new (681 Solo & Efco 251) saws and they cut fine and just looking for a little more HP if it's worth it by a simple modification  by  reducing muffler restriction.

Years ago, we'd drill holes in the baffles or removed part of of the muffler guts and it seemed to work... was louder for sure.

From what I read here (FF), they use dual port mufflers for better power. I see the baffle hole drilling trick is still around and baffle modification as well.

I'm not looking to get too carried away with a muffler mod. but if >>  05% + power was realized for a simple type modification... I might be interested.

The Solo 681 is  Not a CA  type saw but the Efco 251 has some emission stuff;  I have to re-read the 251 operator manual to see what it has (forgot).

I understand with all mod's. >>  carb. re-tuning is required and that's a given for any changes to any engine with >> fuel or ign. changes.  What I don't need is... a hole in the piston from making too much of a change and messing up a good saw.

Thank Ya'

Avery

 

 

[ladylake]

 I think you'ld see good gains on the Efco with a clogged up muff stock, The Solo is kind of a factory hot rod, they most likely have a free flowing muff already.   On my little 40cc Echo CS400 cut times went from 15 seconds to 9 seconds with a muff mod, that had a choked up cat muff.  Turned in to my favorite saw around the mill.  Steve

[Cut4fun]

I would leave the Solo 681 alone. She's hot right out of the box.

[Al_Smith]

As long as you can tune the carb so it has that "4 cycle " sound ,you are safe .If however you can't get enough fuel you take the chance of turning the piston /cylinder into crispy critters .

My favorite example happen a few years back .A certain person who owned a tree service in Cincinati got some info from the net about modding a muffler,so he did and was proud as a peacock about his brand new 088 Stihl . Ran like a scalded ape .

I cautioned him about it but this expert engine man from Canada assured him that a  giant hole in the muffler would be just fine .Well of course the old farm boy doesn't know anything, so I shut up about it .

Sure enough up on flea bay pops a brand new 088 Stihl, cooked top end . That was  about a thousand -1200 dollar boo boo at that time .

[John Mc]

Someone once posted some guidelines about the area of the muffler exhaust port as compared to the exhaust port area coming from the saw. I can't remember what they said, but perhaps one of our resident saw gurus could give us an idea...

John Mc

[John Mc]

Another thought, Avery...

I'm not sure how worried you are about warranty coverage, but if these are new saws, you may want to wait a bit, or do this in a way that's easily reversible. If you are in an area where fire is not a major concern, you could just pull the spark arrestor screen for starters and see how that works, or maybe buy an aftermarket muffler to do your mods on, keeping your original muffler to swap back in if you had a warranty claim.

I still have the catalytic muffler I took off my Jonsered 2152. I wasn't nuts about fiddling around with some of the nasty metals inside without knowing more about what precautions to take, and I figured I had something to go back to if I didn't like the results. I never did get around to modding the non-cat replacement muffler. Just the swap solved my heat problems and gave a noticeable boost in power. I may try it some day.

[Jeff]

Or you could run them stock which is suitable for 99.9% of the population that don't primarily run a saw for a living.  You are building a log house and using a sawmill. You don't have log production as a concern to a paycheck at the end of the week. Leave em alone.

[Al_Smith]

Or you could run them stock which is suitable for 99.9% of the population that don't primarily run a saw for a living. 

--and that remaining  tenth of one percent has 5,000 secret formulas of how to do it .

[John Mc]

I'm generally part of that 99.9%. However, in my case, I was having trouble with my 2152 overheating. It would run just fine for a full day of felling (generally time to cool off between cuts, or lighter loads when limbing). When bucking hardwood for firewood, it would run OK for a couple hours, then stall and have trouble starting again unless I let it cool down first.

I didn't know much about tuning at the time, but wondered if it might be running too lean. I took it to a shop with a good reputation for service. He thought it was set up just fine. At the suggestion of someone here of FF, I swapped out the catalytic muffler for a non-cat one, and rechecked the mixture. All of the problems disappeared. The bit of power boost I noticed was just the icing on the cake. Plus, doing this finally got me off my butt and learned how to set the mixture myself.

John Mc

[smith2bj]

So hearing all what you guys are saying about porting, do you thing that this would be something that is worth doing to my 2171?  It about a year old and if I can get some more power I definately want to do it.  But I dont what to smoke my saw.

[Cut4fun]

2171 muffler is a open can, no baffle inside. Never muffler modded a stock one to see if there was any gains. Never felt I had to on stock being they seemed to breath pretty goo the way they were.

Now on the woods ported ones muffler modded with dual ports using a husky deflector on the side or going through the front brace on front of muffler. Try it on a stock one and let us know. Dont forget to adjust carb and cut plastic stops on L and H to get full adjustments. 

There you go have at it. 

[Al_Smith]

So hearing all what you guys are saying about porting, do you thing that this would be something that is worth doing to my 2171? 

Now don't get the term "porting " confused with reworking the port scheme of a saw engine as opposed to just relieving the pressure on it's muffler .However to get the former to work properly you will have to do the later .Kinda like the chicken and the egg .

[Ax- man]

Someone once posted some guidelines about the area of the muffler exhaust port as compared to the exhaust port area coming from the saw. I can't remember what they said, but perhaps one of our resident saw gurus could give us an idea...

John Mc

I might as well get in on this thread. Enlarge the exhust muffler exit hole about 80 to 90% of the exhaust port.   After that there is really no noticeable gain in power. I have used that guideline for any muffler mod I have done to a saw, plus the the retuning, no problems . Just readjusting your low speed screw alone to provide a richer mix isn't a hard and fast rule. I have had to fiddle with the high speed jet also to find that sweet spot after doing a muffler mod. I like to to make a nice long rip cut or cut a big diameter hardwood log after doing a muffler mod. If the saw falls off in the middle of the cut or dies after making the big cut it is still lean and needs to be richened up. Starting up by the fourth pull is a good sign your close to the right setting. A nice clean acceleration with no bogging or stumbling is another good sign but it is the cutting that is the best test.

A well done muffler mod along with a sharp chain is more than enough to get that extra power kick from a saw. I try not to gut mufflers out but more enlarge baffle holes or add a few holes in the baffles and try to keep the same flow of the exhaust just not so restrictive as a stock muffler. Enlarging the exhaust hole in the muffler is usually enough to get the job done. I also prefer to leave the screens in as I personally don't see them as being restrictive. I know someone will argue this point but that is just my two cents on the subject nothing more.

[H60 Hawk Pilot]

Thank You  Ax-man

You spelled it out fairly well. I'm a big engine builder (diesels) and love engines in general. The little Efco 251 is a fair saw, I'd just like to give it a boost by a simple muffler modification &  understand 80/90 % of exh. port is my guide line. I have a Fuel/ Air Mixture Tester that I bought to set the carb. on a 460 Ford engine that I rebuilt (installed new carb. & intake) in a motor home.

I might use F/A tester on the little saw for tuning but the best test is under power as you mentioned. I remember the best power mixture as 10:1 (by memory) for best power, also the exh. flame is >> deep blue/ purple at best power. Orange or Red color is lean or too rich. I realize that the exh. flame is not visible with the muffler on. I have used this method on race engines and aircraft engines with short stacks; deep blue color does not lie.   

I fired up my Dad's Homelite XL12 a few days ago. The XL12 (old but like new) cuts super and the added noise did not bug me at all. I can't imagine why they smog a little (Efco 251) chain saw like this and I'm 3000 miles from CA... just nuts. I lived in CA in the 80's (4 years) and have met some extreme folks in CA & (overall) common sense is not their stong suit. Lot's of far left or right, not a lot of center fielder's; just my personal opinion, maybe I got it wrong  .

Thank's

Avery

[Frickman]

I'm with Jeff, leave it alone. I earn my living running a saw and have never modified a muffler. If I want to cut faster I just buy a bigger saw. I only remove the spark arrestor screen, that's all. The saw maufacturers have designed their saws to run as efficiently as possible as long as possible. When you start deviating too far from their design you end up destroying saws.

[ladylake]

 I'm for the muff modd, most new saws are way choked up thanks to the EPA. Bigger saws weigh more, it's nice to have added power out of a lighter saw.   Steve

[wickmar]

   In my experience, spark arrestor screens tend to plug up with:   1) Time  2) Too rich a carb setting  3) Too much oil in gas.   Seems like just removing the screen will solve PART of the problem.   Otherwise a carb adjustment and maybe running a quality syn. premix oil would help.   Then you wouldn't have to deal with the expense and potential upper end problems of a muffler mod.
   Just a thought.

         wickmar

[welderskelter]

I have an 066 Stihl that needed something and I just found a muffler that was off an older saw. Before EPA, Ha. I will bet I gained about 25 to 30 percent more power. Lots louder but runs like a raped ape. I took it in to have the settings checked and he said they were fine but give them a final adj. Best thing I ever done to that saw.

[H60 Hawk Pilot]

Welderskelter

I'm with you (mod. exh.) and plan on opening the exhaust up in the next few days. Today, I cleaned all my saws, removed the bars and blew all the saw dust out, air cleaners... the works. I did take alook at the exh. and it's really thick and looks real busy in there and jam packed & lot's of restriction and back pressure.

If I get a  25% +  boost in HP I will be smiling big time  .  The Efco 152 is a fair saw (as it is) and cuts decent with the micro chain set up (not the anti kick chain). I bet with a little modification, she'll run real decent like your Stihl 066 (raped ape).

I think most of the guys are lost whem it comes to mod's. and tuning and rightfully so if they never did this type of work.

Thanks' for the Information. 

I'll let you know my result's when I get her mod'd. up.  I will see how much crapp is in there and go from there.

Avery
     

[weimedog]

I'm a hack..not a saw builder by any stretch of the imagination! So the following are things a typical "hack" can do to have a little fun...DON'T play these games unless the saw is essentially expendable! And certainly re tune the carb if you do anything that might effect flow in anyway. (Last but not least...if its a real working saw, a larger tube with a spark arrester screen inside might be the appropriate thing to do..especially if you work in those dry places where forest fires are possible!)

I mod the mufflers on my hobby saws...and if the saw will be used as a real 'working in the woods' saw...I usually plug all the stock outlets, gut all the internals and for the 70-80cc class cut a hole in the corner towards the clutch/chain brake side and weld or braze in a 3/4inch tube. The mods I have done going straight out the front of the muffler, whether it be a simple enlarged hole, or tube; turn into liabilities when I rock the saw & therefore outlet of the muffler into the wood! The side exits aren't bothered by real work as much. And for a real working saw; don't forget a spark arrester screen..mine are usually on the inside.

A 365 with a 371 cylinder & aftermarket piston...stock ports, just muffler mod and no base gasket (Tri bond 1194)..out runs my woods ported 272XP...if you ever put the 272 and 372 cylinders side by side you would understand. 372 has so much more port area stock than you can even hog out of a 272 without getting real creative! (The true builders can do things I can't)



An in process mod for an old Jonsered 920, Split it open and removed all baffles leaving only the support tubes the mounting bolts go through. Brazed a 3/4 inch dia. tube for the outlet. Also brazed it back together and then ground the rough spots away for looks and painted it black with high temperature resistant paint.




A NOT very practical mod I did for kicks on my GTG fun Saw...It makes lots of noise and cuts pretty fast for what it is..but not practical for a working saw! (Mildly ported 2094 assembled with no base gasket and has stupid compression as a result!)



Last but not least, a muffler mod on a ported 272 done by a local saw builder..and its much faster than stock  only a bit faster (maybe!!) than my basically stock 371 cylinder on a muffler modded 365! Message? A well designed saw stock may still kick butt on a similar sized home modded & ported saw!

[Al_Smith]

The little stub 3/4" tubing like Walter did does pretty good but the key to the whole thing is gutting the muffler .No baffles ,no screen ,no diverter .On a two cycle you have to kind of work backwards .If the exhaust can't get out then the next fuel charge can't get it .To run real good it has to breathe real good .--and no matter what anybody says it takes fuel to make power ---

[H60 Hawk Pilot]

Al Smith & All

Good Pic's and Advice that can be worth a 1000 words to me when I operate on the Efco 152.

My Question:

I saw a 272 XP on Ebay and the owner said that it will start and idle a short time and then shut off. The saw may restart or may not start. They said it had good compression and the pic's provided .. showed a older saw in fair shape (picture wise).
I think it has  24 inch bar & decent chain on it.

I don't really need the 272 XP but like working on them and (almost) fun & teaching my 15 YO.

Again, my question.. is the 272XP a decent saw ?  I see it.. as my mid weight + saw and would be a good back up saw for me and save my Solo 681 from getting used up as my primary saw.

I was guessing, I thought the saw might go for $ 130.00 or less with the engine problem.

What Say Yee ?

Avery

[weimedog]

I like the 272's (actually 61's 268 & 272 all can be ungraded with a little thought to take 272xp cylinders) as they are about as simple as it gets to work on. I would go for a complete saw if you want to build it so you nickle and dime yourself to death looking for parts!

Actually a lot of times a stuck piston will deposit aluminum on the cylinder...and that cylinder can be salvaged. For playing around, aftermarket pistons are fine...I like the Meteors and Episan pistons myself. Foresters are also OK...

To salvage a cylinder with aluminum wiped on it sometimes you can simply sand paper the aluminum off with time and patience....I usually use muriatic acid from a masonry supply store to get most of it off chemically and the sand paper..then hone. Bet Al has a better approach!

But to answer your question..a 272 is a great saw with good solid power when done right; to start the mod game with for a lot of reasons...just don't be upset when you mod the crap out of it and a stock 372 or 681 still hammers it! btw.. I wouldn't touch that 681 and also wouldn't have any so called saw builders who can't back up their work with documented numerical evidence touch it either! They are awesome stock..best left alone!

[H60 Hawk Pilot]

Weimedog

Good Information, I'm going to lay a bid on the 272 XP and see how it goes. I usually get something I bid on  when  I don't  need the item  and  Don't win when I really need the item.. we will see.

Thank's for Info.

Avery

[Al_Smith]

 To salvage a cylinder with aluminum wiped on it sometimes you can simply sand paper the aluminum off with time and patience....I usually use muriatic acid from a masonry supply store to get most of it off chemically and the sand paper..then hone. Bet Al has a better approach!

 

Actually no I don't .The one thing I can say though is don't get impatent with a flao wheel because you can grind right through the plating .Whoever once said that because the nickle alloy plating contains some carbide therefore rendering about like armor plate evidently was a tad mistaken .

I have used a 3M green pad and easy off oven cleaner and got good resuluts .

[Cut4fun]

Al I have actually started drilling the internal baffles out on some saws and leaving baffle in. On mufflers that was a 2 piece and needed the support between front cover to bolt up tight. Otherwise they would pull tight and collapse front cover or the muffler bolts would work lose sometimes.

[Al_Smith]

 I can't remember which saw but I had to use pieces of tubing in the place of the baffles so as not to collapse the front of the muffler . It worked .

[weimedog]

I will have do do as Al says on my 61 muffler to fit it to a 272 cylinder

[Al_Smith]

I think in this discussion of mufflers a point needs to be made for those with less experiance about their function, just as reference .

A majority of modern saw mufflers are what is refered to as "pressure cans " they hold a certain amount of volume and in function are actually a pressure regulating device .The baffles within them just bounce the sound waves or scatter them and they colide with one  another which effectively kind of cancels them out .Not entirely but to some degree .

In doing so though the flow of the exhaust is hindered and as such the incoming transfer portion of the engine is less than optimum for performance . Elimination or modification of these baffles will allow a more unhindered flow and as such produce a bit more power without doing a single thing to the rest of the engine other than perhaps enriching the carb because it will need more fuel .More fuel translates to more power .

Of course along with the baffle modification enlarging the actual exit hole allows for more fuel being transfered and thusly a more powerfull engine which effectively runs cooler .Real simple stuff if you think about it no rocket science involved at all .

[weimedog]

First I have to again state I in no way consider myself to be an expert. I'm a hobbyist hack at best leaning my way to having fun with old saws..I wouldn't touch a new one myself and would never mess with anyone Else's saw!. Leave that to those who know what they are doing! Some people do cross word puzzles to pass time. I bring old Jonsereds, Homelites, and Husqvarna's back to life for my hobby. AND for entertainment at our GTG's mod some of my beater saws for kicks! Also I cut a lot of wood so I might as well make it a hobby..otherwise it would just be a chore! For by far the majority of saw users, stock is by far the best option. Don't mess with a saw unless its expendable, and by all means ignore some of the BS and Bling arguments used to justify spending time and money to hack up a perfectly good saw!

I think two other points need addressing if anyone takes the modification route...first and fore most forget about any warrentee you had after doing any type of modification to a new(er) saw! Also when tuning...don't pay attention to the one's who define success by how many RPM's that saw will turn no load...what counts is how well your saw holds those rpm's in a cut or if a modification allows your saw to now hold a higher RPM than before in the cut!

In that spirit, I like to tune to plug color vs. straight RPM's. Get the initial tune the conventional way..have it "4-stroke' a bit on top (or tach in my case). But really do plug checks after working the saw. I like to run a little rich on my work saws. So I tune my saws to where my plugs are on the darker side of tan..chocolate brown is where they are.

Another thing that can mouse up things are those RPM limited carbs and ignitions. You may think that "4-stroke" sound is the sound of your slightly rich mix on the high rpm's..and it could be your rpm limiting device instead and actually you are still too lean! ANOTHER reason plug checks are so important.

SO. Having said all that. I actually tune with a tach. And set even the modded saws I have to the stock recommended RPM's. Then do a little intuitive tuning along with plug checks to work from there.

(You can replace limited ignitions with unlimited ones..and you can disable the limited carbs as well...discussion for another person another time. I'd rather tune for more power in and around the Stock RPM range for my hobby woods ported saws)

[weimedog]

I will have do do as Al says on my 61 muffler to fit it to a 272 cylinder

[Al_Smith]

 I'm thinking that whatever saw I used the tubing trick on had  a one piece muffler that who ever built the thing had the bright idea it couldn't be tampered with .Hmm guess they never heard of Yankee ingenuity and a die grinder .

Now on other issues I agree with Walter ,don't follow everyones well intended advice if you don't know what you are doing . Get into it a little bit before you go to grinding away like a crazy man .By all  means fiddle with a freebie or several before you turn an 800 dollar saw into a door stop or anchor for a rowboat . Rome wasn't built in a day nor were good tuners .You have to walk first before you run .

[ScottWojo]

What ever you need to know send me an email.  can provide you with tips,  materials and screen.

scott_wojtasik@hotmail.com

[beenthere]

Welcome ScottWojo

Tell us about the tips and materials.
Thanks.

[Sawz all]

Hello, my name is Kevin and this is my first post here at The Forestry Forum.  

I spent a lot of my time learning/building high performance work saws and worked very closley with people I consider to be top notch builders (over at racesaws). There were some really good/helpful people over on racesaws. I made some good friends! That being said, I have a very good understanding of what makes the whole package work.

IMO, if you leave a saw all restricted (without a muffler mod of any sort) the saw will work fine and last a manufacturer's life cycle. If you open up the muffler (mod it), even if you find little or no gains, the saw will breath better/run cooler and have a longer life cycle.  Keep in mind, some saws will have stronger gains than others as far as speed!

Scott Wojo is a friend of mine and he has made several mufflers for saws I have built. We are actually working together right now on a 359 Husky muffler modded/cyl ported saw. I had my friend Herb run a down up down in 10x10 pine and timed it. Next I had Scott build me a muffler to my specifications and ran the same test. The end result was only a hair faster with the modded muffler and a stock cylinder.

I am in the midst of porting this saw right now and in a few weeks I will have the timed cut for this saw with a ported cylinder and wojo muffler. All three of these tests I videoed and will share with you guys when done.

Kevin

[Cut4fun]

Hello, my name is Kevin and this is my first post here at The Forestry Forum.  

Hey Kevin long time.  In this thread you might see some info where I talk about that 266 I sent up to you and getting a like new 66 on a trade. You might be able to answer some of the questions I had.  http://www.forestryforum.com/board/index.php/topic,47753.0.html

Welcome,
Kevin

[weimedog]

I am in the midst of porting this saw right now and in a few weeks I will have the timed cut for this saw with a ported cylinder and wojo muffler. All three of these tests I videoed and will share with you guys when done.

Kevin

Have any pics of the porting & port timing numbers to share? That would be cool..especially if they are from the 200 series Husqvarna's

[Sawz all]

I just got home from work a little while ago.
I can tell you so far:
359 Husky stock timing nbrs
Ex 104*
X-fer 123*
IN 76* BTDC

Kevin

[weimedog]

Do you know the 272XP's? What would you want to change on that 357? Would you rather that intake be down into the 70 to 72 range?  123-104= 19, you going to do anything here? Just curious as some really get into the port timing game...to this point I usually don't and focus on cleaning & a little widening to what I can get away with based on piston skirts & blending so the transitions are smooth from component to component...but that's it..not an expert here. (ie. really don't know squat about changing port timing)


This is on my 272XP, this particular cylinder was built by a local guy who builds fast things for a living. I Did exactly this is on that 272XP cylinder on my 61 too (I don't  and won't do this for a living..only on my personal saws and race bikes)...the cleaned up exhaust and then matched to the exhaust stuff...(You might see the lightly modded transfer peeking out the bottom.)

[Al_Smith]

I can tell you so far:
359 Husky stock timing nbrs
Ex 104*
X-fer 123*
 
Kevin

Hmm "long" exhaust, short blow down .

[Sawz all]

weimedog,
Right off the bat I need you to understand I don't consider myself an expert and it takes a lot of trial and error to find numbers one likes. I don't want to come accross as a know it all, cuz I'm far from it...... That being said; I have done several 272xp's and the last one I did I think came out the best but only after finding out how it worked the other two ways (with different port timing nbrs I chose). Bottom line is all three came out good but the last one had the balance of power/torque I was looking for. I don't really feel comfortable telling you how to set up your saw(s) or how I'd do it. Especially being only on the sight for three days. As time goes on I'll share some things and hope to see other people trying things and all together we will all learn.

Getting set up with the correct porting equipment is an expensive investment in it's self.

On the 359, I am going to alter all three of those port nbrs.

STOCK 272
IN 69*
EX 102*
X-FER 127*
SQUISH .035

The one I liked the best I set up like this:
Ex- 97*
X-FER 118*
IN- 79*
and I forget if I had to make a base gasket or if I ran it w/out to aquir the squish I wanted.

Kevin

[Sawz all]

Hey Al,
Yeah, those are the nbrs.

I can tell you so far:
359 Husky stock timing nbrs
Ex 104*
X-fer 123*
 
Kevin

Hmm "long" exhaust, short blow down .

[Ecopsey]

I just got home from work a little while ago.
I can tell you so far:
359 Husky stock timing nbrs
Ex 104*
X-fer 123*
IN 76* BTDC

Kevin

Hi Kevin those are good #'s to work with for a "good" work saw .. 27* blow down is real nice wish they all had #'s like that.
Need any give me a shout.

[weimedog]

I appreciate the candor Saws all...and thanks for the tips & numbers. And it looks as if this thread has now attracted the attention of some real knowledge.

[Al_Smith]

27 would be but 19 most likely would not ---123 minus 104--19 ,unless I missed something  

[Ecopsey]

27 would be but 19 most likely would not ---123 minus 104--19 ,unless I missed something  

woops my bad sorry Al

[weimedog]

What would you recommend for a 272XP where it purpose is to do some work and to be fun at GTG's after the work is done...just a tad warmer than a pro's work "saw woods" port build?

(Al if you have pics you want put either in a gallery or have posted...email them and I'll build a thread you can add commentary to)

[Al_Smith]

I can't relate to a 272 because I've never worked on one .However the 038 Mag I reworked was right at 100 on the ex then I dropped the cylinder and it was around 102 .Somewhere around 22 blow down more or less .I ran it that way,oodles of power ,a little slow of speed but better than stock .

Soo back in I go,raise it to 94-96 or so that makes it like 28-30 blow down,okay now we got something--almost ---.Back in again and doctored on the upper transfers .That did the trick . There's more that could be done but not on that one .Another  is waiting in the wings for the next go round. The mood has not struck yet though .

[Al_Smith]

  We've got to stop here because we lost half the crowd in the first turn .

Oh my the subject was tuning in a muffler and before you know it we'll be babbling away about finger ports .

To those who just want to pep up the old saw,a simple rework of the muffler if nothing but pulling the screen helps and satisfies 90 percent of the folks without further ado .

Don't get too wound up about a few of us redneck half crazy grease monkeys that are about a half a bubble out of plumb to begin with . We just can't help ourselves .

[weimedog]

I agree. The thing that's becoming more and more apparent to me is the same things conceptually that worked on the old piston port motorcycles work here as well. (Minus the pipes & intake reed valves) Sort of a deja vu experience although the specific details related to specific saws is all new to me. New territory and fun as it's another learning curve to enjoy....

Gordon Jennings would be in hackers heaven here....Oh..By The Way:
http://www.datafan.com/TunersHandbook/2-strokefiltered.html

[Cut4fun]

Yep Kevin the 266 I was referring to you was the one I sent up to you with the clean looking top end.  Glad to see someone get use out of it.
 I got 2 more 372 tore down to cranks right now with a like new looking Mac 805 I dont want no part of working on  and a Partner 550 tore down that I might end up with a 7000 plus topend on in the future.

[Al_Smith]

Gordon Jennings would be in hackers heaven here....Oh..By The Way:
http://www.datafan.com/TunersHandbook/2-strokefiltered.html

I downloaded it a long time ago and printed it out .Between that,Mac Dizzy,several RC forums,motorcycle forums and several chainsaw related sites I just keep plugging along .All that plus a few little "hints " I get along the way .

Put it on the "wheel " map the ports, scratch your head for a week thinking it over and change your mind half dozen times then get with it .Put it back together ,run it,tear it back down and do some more .Stop before you wear the bolts out .

[Sawz all]

I appreciate the candor Saws all...and thanks for the tips & numbers. And it looks as if this thread has now attracted the attention of some real knowledge.

No problem weimedog. But who am I? Chop liver?......, before the "real knowledge"......

Kevin

[weimedog]

I appreciate the candor Saws all...and thanks for the tips & numbers. And it looks as if this thread has now attracted the attention of some real knowledge.

No problem weimedog. But who am I? Chop liver?......, before the "real knowledge"......

Kevin

I doubt it! You are way further along the curve than I am, that I do know. I have seen some of the work from "That other guy" you are referring and its pretty impressive, and therefore tangible. I don't know either one of you guys but I am quite pleased you folks decided to drop in and leave some knowledge behind....

BTW my guess is you probably left that gasket out to help with the torque with that intake number. (Understand I'm basically clueless relative to port timing..just a guess) I would have loved to see how many R's you got out of that thing no load!

[wannabeonetoo]

Looks like the RS crowd has dropped in !!!!!!!!!!   

Steve

[weimedog]

For now. They are in a different league playing a more serious game relative to performance. I can't talk for most, but many are more interested in reliability and / or like in my case just getting an eclectic group of hobby saws to run is a win.  Also the focus here is the forestry side of things. One of the reason's I'm here as there is a lot of knowledge on issues important to me as a landowner & farmer with wood lots. Saw's are tools first and a hobby for me second. BUT the "racesaw" concept sounds like fun for an old clutch head like me!

[Sawz all]

weimedog,
Believe it or not I don't own a tach, I do everything by ear. Sometimes I take certain saws I do over to a friends who has a tach and figure out what the revs are.

Rule of thumb; the higher you take your exhaust the more revs but you loose torque, you have to find a nice balance.
Port shapes and angles all have things to do with the final result. As a porter is porting he or she must be thinking ahead as to down stream effects.

There is a lot to learn and I can tell you I learn something new every time. Anybody who tells you they know everything is full of chit.

Kevin

[weimedog]

 

Again I appreciate the info & insight! Good stuff and I couldn't agree more with your analysis...I'm all ears for insight.

[Sawz all]

 I have seen some of the work from "That other guy" you are referring and its pretty impressive, and therefore tangible. I don't know either one of you guys but I am quite pleased you folks decided to drop in and leave some knowledge behind....

[/quote]

That "other guy" is one of my mentors....

Kevin

[weimedog]

I have seen some of the work from "That other guy" you are referring and its pretty impressive, and therefore tangible. I don't know either one of you guys but I am quite pleased you folks decided to drop in and leave some knowledge behind....

That "other guy" is one of my mentors....

Kevin
[/quote]

Then you are one lucky SOB when it comes to getting saw building insight! (And there for like guilt by association fall under the knowledge umbrella)... There is another guy from the Ontario area I wish would drop in from time to time as well...there are some really good folks out there.

[Al_Smith]

There is a lot to learn and I can tell you I learn something new every time. Anybody who tells you they know everything is full of chit.

Kevin

Truer words were never spoken .

[ScottWojo]

Welcome ScottWojo

Tell us about the tips and materials.
Thanks.

Sorry about the delay.  Been busy and away from the net. 

Not sure what kind of tips you need.  I build my mufflers with stainless pipes,  and stainless screen.  If your going to make a cooler saw,  it should look cool too.

I just meant,  if you have a hard time finding stuff for your saw,  or if you need help figuring out what size pipe to use,  or if you even want to use a pipe.  Or if you just don't want to even do it your self.  I know plenty of muffler makers and can steer you into the right place.

[Al_Smith]

  Oh pshaw ,a rusty muffler works as good as stainless one .Besides that steel is a sight easier to work with than stainless which everybody thinks is the wonder metal of which it is not .

I've seen stainless exhaust sytems on custom cars that will turn as blue as any other metal so what good is it ? I mean after a while the stuff looks like anodized aluminum , how cool is that ?---but it doesn't rust in the true sense of the word for what that's worth .

[weimedog]

Part of the fun is the "chicken chit to chicken soup" concept of taking an old saw and bringing it back to life. There is little of no risk in hacking up a dented and rusty old can of an exhaust and its fairly low tech & easy to do rather effective mods. AND its yours..all elbow grease investment. Many times things like that old Husqvarna 61 or Jonsred 920 were one step away from the scrap pile...they simply aren't worth putting much into from a cost perspective as even all cleaned up they are $150-$200 dollar saws! Having said that... there are the folks who would like to "bling" out new saws and have a performance benefit as well...different groups of folks, both will look to difference places for satisfaction and therefor are reasons and room for both. And why not? Think of all the stuff people put on cars, motorcycles, and trucks etc to make them look and run better. Why not here in this motorsport?

[Al_Smith]

You don't have to have a degree in mechanical engineering nor a degree in It tech tech to rework a saw engine  .

What you need is the tenacity of a wolverine to carry it though .If it works ,fine ,if not so what ,at least you tried .

[weimedog]

You don't have to have a degree in mechanical engineering nor a degree in It tech tech to rework a saw engine  .

What you need is the tenacity of a wolverine to carry it though .If it works ,fine ,if not so what ,at least you tried .

Funny you say that! That's so true....and what you said about "Yankee ingenuity" with a die grinder a few postings back. And if you think about it most of the major innovations of the last 100 years happened without degree's.

[Al_Smith]

Oh yes the famous "McCoy oiler "used on steam engines was the product of a pharimistist ( can't spell ) .Never the less the real McCoy .

[Spike60]

I'm generally part of that 99.9%. However, in my case, I was having trouble with my 2152 overheating. It would run just fine for a full day of felling (generally time to cool off between cuts, or lighter loads when limbing). When bucking hardwood for firewood, it would run OK for a couple hours, then stall and have trouble starting again unless I let it cool down first.


John Mc

What causes this is indeed the cat muffler. In sustained use, the heat from the cat will gradually increase the crankcase temp to the point where the saw will simply not run right due to fuel atomization issues. Take it to a shop, and gee, there's nothing wrong with it. Back to the wood pile and the problem returns. I stopped selling 359's and 2159's due to this problem, and this is why it's so important to get a non-cat 346 when you buy one.

Back to the main topic; muff mods do make more power on most saws in my experience. Some will show more dramatic gains than others. A 372 wakes up pretty nice. Most of the larger Stihls come with a very small outlet hole, and some nice gains can be had by enlarging them.

[Al_Smith]

Thanks to the EPA the saw performance has gotten worse over the years .It's not the fault of the manufacturers ,they have no other choice but to comply with the governmental edicts .

I had to laugh  few years back when one of the guys ran a stock either 181 or 281 Husky  in the 0-100 cc class at one of our GTG's .It was up against souped up 066's ,2100 Huskeys and the like and although it didn't win it did exceptionaly well being 5 cubic inchs .

One of the other participants who fancies himself a guru of saws insisted it was a race engine but declined to take a look through the exhaust to verify that as fact . I was rolling on the ground laughing because I for one knew how well that praticular saw model ran  in stock form .

[Sawz all]

I'm generally part of that 99.9%. However, in my case, I was having trouble with my 2152 overheating. It would run just fine for a full day of felling (generally time to cool off between cuts, or lighter loads when limbing). When bucking hardwood for firewood, it would run OK for a couple hours, then stall and have trouble starting again unless I let it cool down first.


John Mc

What causes this is indeed the cat muffler. In sustained use, the heat from the cat will gradually increase the crankcase temp to the point where the saw will simply not run right due to fuel atomization issues. Take it to a shop, and gee, there's nothing wrong with it. Back to the wood pile and the problem returns. I stopped selling 359's and 2159's due to this problem, and this is why it's so important to get a non-cat 346 when you buy one.

Very good post! I never really thought of it that way, thanks! I know That 359 I'm doing right now had the worst cat in it I've ever seen!

I had a husky 575 that came through with a problem I could not fully duplicate.....once it was running for a while (good and hot) and the guy shut it off he would have a hell of a time trying to get it started.

Kevin

[ScottWojo]

Al,

I know how you feel about stainless.  Sure gun bluing or some other ano looking stuff would be cool too.

And probably just about anything else would be too.   I just like the look of the stainless,  and once the welds are blended in,  they really are nice.   And once it turns color its not a big deal to make it look new again.

And you really do not need to be an engineer to do much of the simple things.  And it doesn't take long for knowledge to replicate and improve itself.    Just have to do it and keep doing it.

[Al_Smith]

Well the stuff is what it is .I'm not opposed to it. Fact a lot of the  bells and whistles on a couple of Harley choppers I had were stainless .You can buff it to look like chrome if you desire .

A saw though isn't a hot rod Harley  but you know different strokes for different folks .