Lakeside53's --361 muffler mod w/photos

Arborist Forum

Help Support Arborist Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.
I'll second SawTroll. Earlier in this thread you'll see he tried the 14mm then a 16 mm; I don't recall that he noted a performance difference, but he left it at 16.

I just finished mine today! :) Thanks Andy; no matter where you're hiding these days! :cheers:

Using the 16mm screen/clamp part numbers in this thread [it seems somebody here has it in their sig line too], you can get a pretty nice fit with a 5/8 X 1/2 spacer tube [roughly .050 wall - the math would be 16th but they leave about 64th each way for clearance]. I do like the look of the 16mm; the Ace Hardware tubes had an ID taper at the ends so a little grinding on the OD to make the end a full half round - the screen went down flush without even a hammer.

The brazing litterally was minutes. I had to put my own twist on it, so I brazed it before drilling and used the tube as a drill guide rather than dremeling a round hole oval. Doubt I saved any time [with an endmill instead of drill though!] over the dremmel oval as grabby as drill bits are, but it was fun to try!

The one part that got me scratching my head, was that I had it in my head I could pull the limitters without removing the screw cowling [and now somebody is going to tell me it can be done], but gave up, removed the intake and the cowling [at this point wishing I'd blown off the saw better] a drywall screw turned a little further after it it hit the lean end, back to rich, and it came right out. I ground off the tab and replaced it, but now wonder if I could have just turned it 180 richer? :confused:
 
Last edited:
Paint is drying!!! Then fixed up with the screen and back on the saw.

Did anyone else notice this exit seems to get as much or more volume as the factory? Maybe just the better angle for my non-scientific handtest! I didn't notice a particular increase in noise either - maybe a bit deeper but not louder.
 
Uber-Scientific test equipment! The torque-test on the left gave me the best feel at 1/4richer over original [right at limit]: for both before and after. Is that strange?

The power test (picture doesn't show it well, but bar [25"; RSC freshly ground, fairly agressive rakers] has a little length until the middle then just barely exits until the very bottom) was a half dry stump, hackberry perhaps?, monitored with the "nano-second chronograph" on the right. The high end torque was nice, but my first attempt after the mod was 24 seconds just like the first test [original muff, 1/4turn rich]. Both times I stalled right before the bottom, and I fuddled getting back to RPMs worse on the "after" run. However, if operator efficieny could be considered to be offset by the growing diameter [about 1/2" per cut], I did probaby gain 10-20% as I got it down to 20 by the 4th or so, with a light touch and really backing off at the bottom.

That seem about right?

Anyone know if I should get a new limitter cap, or since the old one went on fine, assume the setting won't wander around?
 
Last edited:
The picture labeled "nobar" is more "look Ma no hands" it's there, just can't see it being right at the end.

I didn't tach it [I realized I can only get to 10K 4cycle], but it dogged at 1/4turn more and high revved at about 1/2 less; that seems I could run a bit leaner and more rev, but I liked the torque test there - that seem about right? As someone [THALL perhaps] noted the 4cyle is a bit hard to hear even muff modded.

Also, I had to play with the idle [didn't even grind the limit on that one though] a bit before the muffmod, but think I took it right back to original after, did have to bring down the idle speed though to stop the chain after the muffmod. Maybe a just a bit faster idle now than stock, but as soon as I got the chain to stop consitantly, I was happy.
 
Last edited:
Make the images a bit more visable:


attachment.php


attachment.php


attachment.php


attachment.php
 
some mod assistance

any northern michigan guys that could give some assistance with a muffler mod or a couple. I would like to mod the poulan and then maybe the 372. wouldn't mind a little over sight and help with tuning, also welding/brazin not my specialty.

thanks.
 
Requesting pics for 359 mod, going out sides, not front

I'm looking to mod the muffler on a 359 I just got recently.

Anyone have any pics of a mod that has the pipes or gills on the side(s)?

I've seen a few that have opened the front, with either pipes and/or washer/screen, but want to stay away from the front due to the type of cutting I'll do with the saw. The muffler will be butted up against the tree while I'm cutting. I'm trying to avoid the excessive heat to my hand which is holding the bar.

Regards,
TT
 
Time for my dumb ???

I am modding a MS290. I have drilled all the holes I am comfortable with for now..I have opened up the front shield and removed the limiter caps...

My question has to do with the limiter caps..Is it better to....

A. tune saw then reinstall the caps

B. trim off the tab reinstall the limiter caps then tune...

My main concern is if I trim off the tabs the screws may turn while I run the saw.. I betting this is not the case but I want to make sure..

Thanks in advance.....


Found the answer....



"Get A drywall screw, pull both limiter caps cut tabs ,put limiter caps back in. Then adjust, start 1 full turn out on both after each adjustment readjust (LA) idle screw. Should be about 13500-14000 RPM's. I leave mine a little in the "ROUGH" (RICH) just to be cautious. Hope this helped"
 
Last edited:
The exit port on the 660 mufflers is very restrictive. Get a die grinder and open up the factory exit at the very least. If you can afford to get a dual port front cover and let your saw breath.
 
i was reading some people like to lean the saw up a bit with a MM and some do opposite. so if you MM a saw and richen it up, it will cut faster than a stock muffler tuned correctly? might be a dumb question but im just trying to learn. thanks
 
i was reading some people like to lean the saw up a bit with a MM and some do opposite. so if you MM a saw and richen it up, it will cut faster than a stock muffler tuned correctly? might be a dumb question but im just trying to learn. thanks

If you drill the holes it will lean out the saw. You will have to reset the carb to richen things back up......

Yes drilling the holes and resetting the carb made my saw cut faster...
 
If you drill the holes it will lean out the saw. You will have to reset the carb to richen things back up......

Yes drilling the holes and resetting the carb made my saw cut faster...

alright i was confused i thought the saw itself would actually be running leaner. my buddy has his 460 pushing 16k rpm
 
alright i was confused i thought the saw itself would actually be running leaner. my buddy has his 460 pushing 16k rpm
The richer fuel mixture means it also gets a bit more lubricant. Also a lean mixture burns too hot and will eventually trash the piston (and probably more).
A lean saw will run faster free turning RPM but it lacks torque when put into the wood.
 
Modded J 621

Did my first muffler mod lastnite. I ground off the lip around the factory hole, then drilled in through the baffle with two 3/8 holes then drilled two smaller holes next two the factory hole and then mig welded a 1" square tube cut at an angle out the front. I would have gotten more in depth with it but i'm learning, addicted now tho. I had to tune the carb just a bit but it is snappier in the throttle and gained a louded voice.
 
just some pics of my 660 muf in stock form is there a need to mod this?

I finally modded mine and I wish I had done it sooner. But I didn't want to make the saw significantly louder.

So I simply drilled one extra hole in the box and in the cover (see the pic). The extra hole in the box increased the area by about 20%. The extra hole in the cover increased the area by 38%, which isn't insignificant. While I took my time doing it, this could probably be done in ten minutes (don't forget to wirebrush the screen while you're there).

The first thing I realized when I restarted the saw was that the chain was running in idle. Aha, something is happier. I also found with this "minor mod" that the saw noise didn't increase significantly AND I was able to re-tune without messing with the carb screw limiters.

Offhand I would say the saw cuts about 20% faster.
 
Dude did the same mod to mine today and had to adjust carb but F:censored: wot a difference ,:jawdrop:In the pic ya posted it looks like she might be runnin lean or something,what fuel mix ya running?:greenchainsaw:
 
Back
Top