Dumb muffler mod question

[Dan Forsh]

I haven't done this before, so let me get it straight.

Ideally the outlet of the muffler should be about 80% of the exhaust port area of the cylinder?

Once you've modder the muffler so your saw is a "screamer" how do you then know where to tune it to?

I hear people say you have to richener it up on the carb, but where to?

Screamer = higher revs so you can't tach it unless you have a number in mind.

If you go richer on the H screw you are going to drop the revs right?

 

[djohn]

Best to richen it until it just barely smooths out in the cut. (smooths out rather then 4 stroking)

 

[Bowtie]

Best to richen it until it just barely smooths out in the cut. (smooths out rather then 4 stroking)

Ok, I understand that. But it is a little difficulet to do that by yourself while running the saw. Some rap the saw to WOT not in the cut and adjust it until it barely 4-strokes. i have been doing this since I dont have a tach yet, but its on the way.

 

[West Texas]

+1 Agree with the advice above; set the "L" jet for easy start and idle in conjunction with the idle adjustment. Then at Wide Open Throttle (WOT), open up the "H" jet until it just starts to make a '4 cycle' sound, or 'blubber' if you don't understand what a '4 cycle' sound means. Then when you put the saw into a log at WOT the engine sound will smooth out to a nice high rpm pitch with no 'blubber' or '4 cycle' sound.

I have a Stihl tack and still use this method to tune my saws after a muffler mod; then, I check the rpms, to be sure its running at or above the recommend 'stock' rpm, if not, then I fine tune more till I get the max performance out of the saw. I do this final tuning while cutting up a practice log. The bottom line is performance in the cut. But, if you err, err on the rich side, as tuning it too lean is bad for the piston/cylinder on your saw. Good luck.

 

[Lakeside53]

Ok, I understand that. But it is a little difficulet to do that by yourself while running the saw. Some rap the saw to WOT not in the cut and adjust it until it barely 4-strokes. i have been doing this since I dont have a tach yet, but its on the way.

you can easily do it by yourself... just stop cutting, make a tiny adjustment, start cutting, repeat as required.. etc..

 

[Bowtie]

you can easily do it by yourself... just stop cutting, make a tiny adjustment, start cutting, repeat as required.. etc..

Andy, that requires more patience than I currently have. But this dog can learn new tricks.

 

[Lakeside53]

You don't ave the patience for 30 seconds of adjustmets? lolol

 

[Bowtie]

I think it will be easier with the new tach. My ear starts to fool me after multiple minor adjustments and I grow weary of the process. I think I have gotten close to optimum with all my saws, but I want them fine tuned.

 

[Lakeside53]

lolol -the only was to "fine tune" them is by ear or timed cuts. The tach is only a rough guide... like WOT setting..

A 361 without a muffer mod is a bear to tune by ear though...

 

[HUSKYMAN]

I never will buy a tach. All it will do is tell me all my saws are setup wrong

 

[Bowtie]

lolol -the only was to "fine tune" them is by ear or timed cuts. The tach is only a rough guide... like WOT setting..

A 361 without a muffer mod is a bear to tune by ear though...

Guess I learned something tonight. I thought tuning in the cut and at WOT by ear wasnt the best way. Ok, Jason, back to patience...lol

 

[djohn]

Better to error on the side of caution though and have it a little rich (burble) then lean (scream).

Not hard to stop cutting, get the screwdriver out and fine tune...but some people want to put on non rev limiting coils so they can tune with tach. LOL, just bustin Brad's balls with that one ;p I think he just wants the extra RPM's ROTF

 

[Lakeside53]

Yep.. you can set a saw "by the book": and it can be completely wrong... use the ear, check with a tach for overspeed etc... Long bars will tend to give leaner than optimal settings; short richer... In any case, ignore the quest for "perfection" and err on the rich side. Won't make an rch worth of difference in your real world cut times..

 

[Bowtie]

From what I read I have been doing it right then. I always listen to how the saw is rapping in the cut. I believe the easiest saws that I have run to tell is the 026 and the 034/036. These 2 are easy. the 441 fools me, but plug color looks good and the 361 I dont have enough time on to learn. I have had a few minor low idle issues with the 361, but the temperatures were drastically different all 3 times I have used it. At WOT the 361 has run awesome. I have made a few adjustments on the high side for temp and way different barometric pressure changes.

 

[country boy]

I modded both of my saws Not to be braggin but purty crafty with the plasma cutter and welder :monkey: But an idiot when it comes to tunen saws I took both of mine to a local dealer he started out as a logger and has been selling stihl saws for a long time so he knows what hes doin. Both time s been in there he'll get em tuned in and ask me if i need anything else and both times get a 6 pack of mix , jug of chail lube and he tuned the saws for free. Just makes me feel a lil bit better having somebody else do it that knows what there doing than me tunen it and blowin it up.

 

[046]

here.... this is worth reading, instructions on how to size exhaust port
http://www.arboristsite.com/showpost.php?p=167495&postcount=5

 

[Bowtie]

I modded both of my saws Not to be braggin but purty crafty with the plasma cutter and welder :monkey: But an idiot when it comes to tunen saws I took both of mine to a local dealer he started out as a logger and has been selling stihl saws for a long time so he knows what hes doin. Both time s been in there he'll get em tuned in and ask me if i need anything else and both times get a 6 pack of mix , jug of chail lube and he tuned the saws for free. Just makes me feel a lil bit better having somebody else do it that knows what there doing than me tunen it and blowin it up.

I did take my 441 back to the dealer after about 10 tanks and he checked the adjustments. I did this because he is a good dude, smart with saws, and it was free. He asked if I had messed with the adjustments. I told him yeah, almost every time I use it. He said, well, it tachs right, accelerates well, so you must be doing something right. I finally found a good dealer.

 

[country boy]

I did take my 441 back to the dealer after about 10 tanks and he checked the adjustments. I did this because he is a good dude, smart with saws, and it was free. He asked if I had messed with the adjustments. I told him yeah, almost every time I use it. He said, well, it tachs right, accelerates well, so you must be doing something right. I finally found a good dealer.

Glad to hear you have a good dealer.I take my to main saws a husky and jonsered to the local stihl dealer . Super nice amish fella. I kinda feel bad because i have never bought any saws from him but i do buy stihl chain and oils from him. Every time i walk in there with one of my saws i tease him (your not goin to kick me outa here carrin these saw in here are ya) and always the same reply na one of these days youll come around and buy a real saw. One of these days i just might try my luck at one of them stihls just because hes a great guy to deal with and actually knows chainsaws. I still love my swedish saws though

 

[Bowtie]

Glad to hear you have a good dealer.I take my to main saws a husky and jonsered to the local stihl dealer . Super nice amish fella. I kinda feel bad because i have never bought any saws from him but i do buy stihl chain and oils from him. Every time i walk in there with one of my saws i tease him (your not goin to kick me outa here carrin these saw in here are ya) and always the same reply na one of these days youll come around and buy a real saw. One of these days i just might try my luck at one of them stihls just because hes a great guy to deal with and actually knows chainsaws. I still love my swedish saws though

Those are all good saws. We spend way too much time bashing saw brands. Im as guilty as anyone. That sounds like a dang good dealer!

 

[scotclayshooter]

I haven't done this before, so let me get it straight.

Ideally the outlet of the muffler should be about 80% of the exhaust port area of the cylinder?

Once you've modder the muffler so your saw is a "screamer" how do you then know where to tune it to?

I hear people say you have to richener it up on the carb, but where to?

Screamer = higher revs so you can't tach it unless you have a number in mind.

If you go richer on the H screw you are going to drop the revs right?

Blsnelling recomends 125% I guess for a work saw its not just overly critical.
I just got a tach you wouldnt belive how small an adjustment it takes on the h to go between 13,000 and 15,600!!!!! poor little 025 lol
I learned about he tuning by ear from the madsens tuning site but it all sounded the same until i listened with headphones try it it makes a huge difference (laptop speakers are crap)
The 025 seems to like running about 14,200 any less and it will 4stroke in the cut