Please Explain What A Muffler Mod Is

[Basso]

HELLO.....I'm pretty new to this forum, but I have seen a lot of posts about muffler modifications. Is it basically about taking the insides of the muffler out so it can release the exhaust faster ? Do you just take the muffler off the saw, cut it in half, gut it and then weld it back together ? Sounds simple....but nothing is ever simple !!!! So, what's the word ? Thanks.

 

[dtnodya]

There's lots of threads on muffler mods but yeah, taking the inside out of the mufflers (if there's anything in there) and making a hole/small holes/custom hole with pipe welded ... Basically, more air can flow so you richen up the H screw to compensate and your saw will run stronger, cooler, and louder. You burn more gas because it can be burned faster (basically) ... But if you don't richen the high speed screw then ka-boom!

 

[Ray Bennett]

Where do you live in Maryland, I have done many muffler mods with no problems ever. Im in Clear Spring, If you are near buy we can make your saw scream like you never thought it could. Also what saw(s) are you considering modding?

 

[Gologit]

Basso...if you get a chance, use the search function. Theres probably been more information about muffler mods on there than any other single topic. (except for oil to gas ratios and we don't want to get THAT started again) Theres a wealth of information here. Start with the search function and then come back here to fine tune what you want to know. Muffler mods really open a saw's potential and let it run like it should.

 

[timberwolf]

HS needs adjustment as mentioned above, but LS often needs more adjustment than high, easy to have a saw too lean on LS and score the cyl while ideling.

In a way LS adjustment is more difficult, HS can be set by tach, by cut time and by ear. LS is a bit more a feeling thing, as well as letting the saw idle and loads up and delays on spool up (too rich) or if the RPM starts to climb (too lean). Also playing with idle stop adjustment it is posible to have the saw stay running at idle but be out of wack on the LS.

 

[dtnodya]

HS needs adjustment as mentioned above, but LS often needs more adjustment than high, easy to have a saw too lean on LS and score the cyl while ideling.

In a way LS adjustment is more difficult, HS can be set by tach, by cut time and by ear. LS is a bit more a feeling thing, as well as letting the saw idle and loads up and delays on spool up (too rich) or if the RPM starts to climb (too lean). Also playing with idle stop adjustment it is posible to have the saw stay running at idle but be out of wack on the LS.

So how do you know where the L needle is supposed to be? Do you just make it like 1/8 turn richer (or something)? Or are you saying that, if the saw is running 'wrong' at idle then make adjustments to the L needle?

 

[Ray Bennett]

Timberwolf is correct about the L adjust, I over looked mentioning it because it is so simple. You will notice right off if it is too lean cause your RPM's will probably increase enough to make the chain move. Simply open the L screw until the saw returns to the proper RPM. If you get to rich the saw will stull or run rough at idle.

So how do you know where the L needle is supposed to be? Do you just make it like 1/8 turn richer (or something)? Or are you saying that, if the saw is running 'wrong' at idle then make adjustments to the L needle?

This will vary depending on how much you opened the muffler, I usually end up moving the L screw between 1/8th and 1/4 turn. I have never had to mess with the LA adjustment unless the saw was all messed up from the start. Then like someone said it gets a little tricky. If you dont move the LA adjustment it should not be that difficult.

 

[timberwolf]

I have run into some situations where the the LS needs to be richened and then the HS actually needs to be leaned.

Walboro 194 with a mild increase to the stock opening.

With openings up over 150% of the port area I have found tweaking the idle stop is needed, with very big openings bringing the idle up until the chain just stops moving is needed to be able to adjust the carb such that the saw does not load up and hesitate on spool up or get to lean in the mid range.

 

[RiverRat2]

L setting

So how do you know where the L needle is supposed to be? Do you just make it like 1/8 turn richer (or something)? Or are you saying that, if the saw is running 'wrong' at idle then make adjustments to the L needle?

easiest way,,, after your mods or with out mods,,, make sure the fuel tank is @least 1/2 full or more,,, warm up saw,,,,,, set idle about 27-2800 iif no tach when chain stops running, adjust L in (clockwise) until engine starts to surge, remember where the adjustment slot is then, now back it out, or anti clockwise, the engine should smooth out, keep going until you hear it start to load up.... another adjuster screw slot mental image,,,,,, now turn it back in to the 1/2 way point between the two mental images and it should be set...

Plagerized from Madsens.............. http://web.archive.org/web/20051018212959/www.madsens1.com/sawtune.htm

 

[dtnodya]

easiest way,,, after your mods or with out mods,,, make sure the fuel tank is @least 1/2 full or more,,, warm up saw,,,,,, set idle about 27-2800 iif no tach when chain stops running, adjust L in (clockwise) until engine starts to surge, remember where the adjustment slot is then, now back it out, or anti clockwise, the engine should smooth out, keep going until you hear it start to load up.... another adjuster screw slot mental image,,,,,, now turn it back in to the 1/2 way point between the two mental images and it should be set...

Plagerized from Madsens.............. http://web.archive.org/web/20051018212959/www.madsens1.com/sawtune.htm

Thx for the link! What happened to that site anyways?

I see what you are saying about the LS now. Thx for the info ....