*****IF YOU ARE USING A MODDED MUFFLER IN A FOREST INSTALL A SPARK ARRESTOR!! *****

Your right on. The engine is a larger system than most people consider. The exhaust is one aspect that has to work with everything else in the chain. making giant exit holes is not working as a team. Controlling the temperature window is huge for controlling many important aspects of an engine. The metals used, have an temp operating range, the oils have an operating range, the tolerances are effected by temperature, the air fuel ratio is majorly effected by temp... I hate computers in vehicles but the power you can get out of an engine by tightly controlling every aspect is amazing.

Great video Tinman. I got a harsh lesson in the science behind 2-stroke engineering in my youth and further experience in the 4-stroke world in my teens. That ratio you mentioned is so important. I recently worked on a saw with a couple of beautifully crafted, monstrous tubes poking out of the front of the muffler. I was addressing a totally separate issue, but the owner also mentioned that he thought the saw seemed to lack low end grunt. When I made mention of his fancy muffler possibly being a factor, he firmly discounted my opinion... Oh well! Thanks for putting out such a detailed explanation and sensible video. Bless’ns to ya, Tedd

Bless you Tinman for sharing your detailed explanations and using visuals to help educate us all!!!

Nice video, I appreciate you taking the time to lay it out so thoroughly. Enjoying the channel, keep up the good work!!

you ny far have one of the best explanations of exhaust mod i do the same on stock saws in my shop. cut out the center of the baffle 2 3/4 inside pipes no longer than an inch love your channel keep up the amazing work

I agree. Getting the back pressure wave timed is the key. The results from you get from dirt bike expansion chambers that are tuned for different applications is easily noticeable

Great information as usual. I just built an 038 magnum 2 and your videos were a huge help. I wish I'd seen this one before I started carving on the muffler but I guess I got lucky cause it sounds great and runs like a beast!

Love it brother. “A muffler is more than just a sound deadening device”! Couldn’t have sed it better especially with two stroke motors! The resonator in a two stroke is where it makes a lot of its power! And when you create to much air flow then the power goes right out the holes! And if you crush the flow or choke it down to much where it can breath enough to make good power then you get the same result! It’s a fine line of a happy medium to get it right nothing wrong with testing these things out but I always keep that in mind! I always looked at my KX 250 and if I got a big dent in my pipe you could immediately feel the power difference! Same thing with are chainsaws just on a much smaller level! Great video brother I need to get your contact info! I am sure you are busy but I have seen your work! And it is crazy the power that you are getting out of these saw truly gifted brother! The Homelite that you did for Buckin and that 044 crazy brother just awesome! I have a older but very well taken care of MS391. She isn’t even close to my best saw but she is my favorite I have had her for more than 15 years! And she has cut more wood and made me more money and got me through more cold winters. Than all of my other saw combined she has never let me down and always start right up. And I would love to see what kind of power I/ we could get out of her. The 391 is a saw I think doesn’t get her dew but for the price you can’t beat it and mine has put plenty of pro saw to shame! Thank you sir love the video good luck and god bless! 🍻

Appreciate you and your time. Thank you!

Florida boy here, 90 degree weather, only cut pine and live oak mostly. I bought a poulan 4620 avl many years ago new. Off the shelf it wouldnt get out of its own way, the 20 inch bar was laughable. I opened the muffler, removed the baffle, removed the exhaust deflector and spark arrestor, drilled it out to 1/2 inch and adjusted the jets. Night and day difference. I can throw it on a shelf for a year, still fires right up and cuts anything I need to cut. I have to buy another saw now, watching you has made me want to port one , can't touch my poulan it runs to good. Definitely in favor of removing the baffle and spark arrestor on a hot weather home owner saw if it has a high speed jet adjustment.

Great video!! You have a way of explaining it so all can understand! 👍👍

Like you tune info / tutorials … straight to the point and, well explained!

I'm with you on muffle mods. 2 stroke exhaust is a whole science in its self. they need the return sound waves to perform.

Always check your spark plugs reading every now and then to can tell a guy alot

Thanks for the great information, so much knowledge!! Appreciate it !! 🔥🔥

Thank you Tin Man I always learn so much watching your videos

I'm definitely intrigued on the big pipe builds . Expansion pipes on big saws . just freaking cool lol ..

That’s why when tuning your saw in professional applications you tune your saw after running a tank of fuel through it fill up and then tune and you keep your tuning driver with you

Great video thanks for the excellent advice. Many need to hear this.

Scavaging is a huge thing in 2 strokes. Sonic waves back flow determine powerband as well this is why the larger pipes .. Fatter and shorter or longer and thinner depending on torque you want or powerband .. We need to make a power exhaust valve system for a saw or a rotary type valve system.

I agree with this. I over ported my stock MS440 muffler. I ordered a new stock cover that I will make a very small hole in to start.

All my experience comes from modding 4 strokes where you want to completely as much as possible evacuate the cylinder. But you do that in a 2 stroke and you loose your charge out the exhaust. Never really thought about that, but it makes sense. Glad I watched this before attempting to mod my muffler. Also been watching your porting series.

It is a fickle thing. I have learned that less extreme size holes or openings work best for my applications. Most of my saws are not ported. It’s all different tho. Great content as usual

The 52mm meteor piston kit fits the huztl 52 cylinder perfect and it’s a great little topend to port... I’m definitely liking the Hyway with a popup in 52mm I’m still sanding my piston and easing all my edges in whatever topend I’m using... any heavy metal plate inside of the can muffler is bad...it’s a heat sync... that heavy metal should be as far away from the exhaust port as possible. It would definitely make sense to have the face plate (6 degree curve or whatever the focus the sound waves back into the center of the exhaust port window... ) like a resonator type pipe... I’m trying to make a bell type muffler design that ports off in four different directions. The ms391 runs 35% better without that crazy tight muffler! I think that’s what causes their bearing problems...too!

On an auto tune saw, it seems like their is less possibly to lose power. I just got a 545 mark 2 and used a 3/8 bit to saw through a baffle which allows a pretty direct path for the gas to escape. Saw runs great.

Thank you Wiseman humbleness is the key thank you sir very pleasant to learn from

Totally agree that you don’t wanna open it up too much, the small two strokes need a certain amount of back pressure to run properly and be able to even tune it. It’s a delicate balance of making it slightly bigger to get more flow but not lose too much back pressure.

This is great info! Loving your channel! Thanks a bunch! Question- 60-70% opening for stock. What's your recommendation for the average ported saw? Thanks

I put a 3/8" hole then tig welded a 1/2" long piece of tubing right in the center of my 350 it's the open muffler design inside,I left the top factory hole in it also with the screen removed. I then adjusted the high side up on the carb because i had a bogging ,I went with a ngk 7r plug and I run klotz 2 cycle oil with ethanol free gas. I love the smell of the klotz from from the years of racing motocross. The ethanol free gas saves the internals including carb parts

Cool vid. I experienced that with too large a mod opening in the muffler, I ran into an idling problem where I couldn't get it to idle without the chain moving. Keeping the rpms low enough to stop the chain movement would kill the engine. I suppose that equates with the engine being too lean that you spoke about.

Love the info keep it coming👍👍👍👍👍👍👍😎

Great video , something to throw at u ,in 2 stroke go karts , we add pipe length between header and muffler , every inch longer gives u more low end and knocks about 100 rpm down . If u shorten pipe u gain rpm and lose a tad low end . So I noticed out west for a stihl . They make a spacer about 1/2 thick to space muffler out from block . Theoretically it would gain low end with that . It would also keep heat down . Your thoughts ,

Awesome video, thanks for sharing this information

Definitely do a 75cc kit on your 365! I did one on a dead 1997 371xpg. Turned out really good.

Your videos are helpful, thanks.

Love it! I’m new to two stroke. Your explanation of it being like a syringe is awesome. I’m hoping to restore Old Macs. Still learning the basics right now. Trying to master carb adjustments. Keep the videos coming they are great!

Another great tutorial! I totally agree! Keep em coming!👍👍👍👍🙏🙏🙏🙏🇺🇸🇺🇸🇺🇸🇺🇸

The "divider" is the baffle. That's how mufflers work to cut down their report. The elongated and routed space causes the expansion to happen slower, like the suppressor on a firearm.

U got it brother. I'm a firm believer that just big enough makes most power. I'm a logger play with my own saws so I can experiment. Gotta keep torque in heat out.Lol.p.s.ironhorse a friend of mine. He's gonna do a cutting video with me here eventually.we'll have some nice saws cutting.

Great video tinman!👍😎🤙🤙💯

I agree 100% I do most of mine dual port with two "tubes" out the front corners (on ported saws) I have found gains when I leave the tubes about 2" long and extend the tube inside the muffler to within 1/2"-3/4" or so of the back of the muffler inside (on mufflers that are an empty can) VS. a tube that is 1/2" long and flush with the inside of the front of the muffler. They dump heat/stay cool and still flow much better while retaining some of the "bounce back". I am in the same boat and in agreement that we all have our own methods. Often we end up with similar results from completely different designs. Thanks for sharing! There's only one way to gain true knowledge in my eyes and that's first hand experience like you're doing. Only one way to find out what works and what doesn't.......... get out there and do it ;) We can all learn from each other. Whether it's a lot or a little, it's still learning. You tube is a great community for us like minded people. thanks again and keep up the great work!

Thanks for sharing your knowledge and experience Tinman 👊

Nice video mate. I made a complete tube exhaust inside the original 372 muffler box it's a straight pipe to the end of the box plugged at the end then about 25mm back from the front of the main pipe a 3/4" pipe comes out the side slightly on-top of the main tube which is 1-1/4" diameter and sweeps slightly upwards inside the muffler box. This along with my porting and the higher flow air box I made it really does pull like a mule And compared to my mates 372 the high jet it's half a turn more and I will nearly cut double what he can in a day. Once my exhaust warms up that's when it really pulls air through. And I have noticed my saw will run cooler then a stock one.

Excellent explanation. New subber here 👍

Love the 12 gauge shotgun barrel muffler!! 👍👍 I think I'm gonna make one with a 20 gauge barrel . I'm gonna leave the bead on , hell maybe I can find one with choke tubes..... think of the tuning possibilities🤠

JUST SUBSCRIBED! From buckin and iron horse. Do lots of landscaping and tree work on my channel. You’ve been great to learn from. I’m working on my 450 rancher and my top handle and taking tips from ya

I have a 562xp auto tune, could you show the modded muffler on your 562 so I can see what I can possibly do? Just came over from buckn’s channel and he was right, you have a great channel my friend 👍

the easiest modification is to port match the muffler openings to equal the size of the exhaust port on the engine. I also drilled and notched the baffle to increase the exhaust flow. I did not alter or modify the spark arrestor. I'm using a small 42cc poulan with a 18 inch bar and chain. I filed down the rakers about 1mm to 2mm to get a faster cut.

Thanks Tinman , I was probably guilty of going to big on first couple mods. Didn't burn them down thankfully.

Great video thanks for sharing

Great info. I have a few that need some work. This will help give me a starting point!! Thanks!!

2stroke exhaust tuning is a balance between back pressure and air flow, but manufacturers also have to take noise levels into consideration for regulations in different countries. By opening up the muffler you can get rid of that noise regulation and let the saw breathe. You will have to retune the saw for the additional airflow. As with all these mods, sometimes less is more.

I was wondering why you didn't mod the muffler on the Echo 670. I think your pinned comment answers that question, not knowing who was going to wind up with the saw or what environment it would be used in. Thanks for the great info.

Great stuff! I agree with you smaller might be a little better.

On my 455 I have 3 1” cuts that I folded to make Louvre in the top chain side instead of putting a hole.

I learn so much from you.. So if i am working on fed lands and have to run a screen. How often should you have to.clean the screen? At home i just lose the screen and thought that was enough, on mystihl 361. Now im looking at a 562

I'd love to see a smoke test on a muffler super slow motion. Plexiglas cutout on a muffler. Be awesome feed it smoke and test different mufflers. Be awesome

Thanks and awesome video

Well said. I enjoy your channel stay humble keep up the good work

Good Stuff!

I’ve seen full on race 2 strokes with a great big expansion chambers with tiny little exhaust tips on the outlet. ??

I agree to open and you can run lean. My MS460 was boiling the bar oil the muffler was to hot. I don't think the saw was ported but it has allot of compression. I bought a pre-built Muffler from Bailey's with dual ports on the muffler it made all of the difference in the world. I runs great and I don't remember what the baffle looked like but I think it was 2 pieces so you could take some of the baffle out. I run it like it was built and not more heat problems. I don't think it takes much to make them run well with out being too lean. Great video!!!

What are your thoughts on the west coast saw bark box and the Egan straight shot for the stihl saws

The scrench is now also a pointer😀

Heya mister i would love to know the best books youve read on 2 stroke...

I wonder if any sort of heat sink or fins go increase surface are could help dissipate heart away from the saw.

I appreciate the power increase per noise increase from a muffler mod. I try to keep it slightly smaller than the exaust port overall size. One other thing I NEVER do is a front mod, too much noise increase and it seems to not get as much power than the same size hole somewhere on the side of the muffler. One reason why I'm not a big fan of west coast saw bark box (love the rest of their product line though), or a straight shot.

The Echo 4910 muffler is the most stock breathable muffler out there! No divider, only a restrictor tube. After shutting it down, I can touch the muffler. Yes, it is hot, but not enough to burn my skin. Echo has the best stock mufflers out there!

You're a man after my own heart, Tinman. The 12 gauge exhaust port... that muffler is DEADLY! I am having hot start issues with my 266 that I put the meteor big bore top end in. I suspect the stock muffler is to blame. I'm not sure how to get it apart without making a mess of it, to get the baffle out.

New subscriber buddy came over from Ironhorse. Great content. Thank you for the info.🌲❤🌲✊

This is brilliant I was at my 385xp and my 365 I drilled both dividers in both mufflers 3 holes in each just to let out heat was I right to do or wrong plz

Why are stock mods so poor? Nice one, stopped me from ripping big holes in all me saws! 😁

Do you guys think there is a market for after market mods for saws? Boost systems etc...

I built a muffler for my saw and like you say. It sounded great but i lost power. So i went back to stock.

Thank you!!

Ive recently seen muffler spacer for sale on ebay or amazon,seller says better than muff mod whats your thoughts on them?

on my 55 husqvarna ,i changed the clogged spark arrester, put in a new one ,know its won't start as good . do i have to change the carb settings and open up the high and low jets? nice info!!!

Tinman, magnesium piston in the 400 m ,im hearing so many conflicting opinions? Will the coating eventually peel and could end up in the crankcase ? Thinking of buying one but I'm divided, not sure which way to go ! Should I rather opt for the 362,don't really want to go more upwards to the 462 to big as I'm only cutting a trailer load at a time! I really value your opinion and I thank you in advance. Gunter

Tinman...enjoy your channel....i have a shindiawa 695 pro i loaned to a friend...big mistake...they put straight gas in by mistake...cant find a cylinder...piston for it...any i deas as to what to do cause it has always cut like a beast ?

Could pipes from like performance rc cars and planes work on a saw, or pipes from wamed up 50 to 100 cc two stroke bikes be fabbed and tuned for saws. The drawback being size.

Good info:)

what about a saw like a dolmar ps-6100 that has reed valves on a clean air(no fuel) intake port that opens before the main air/fuel port? any need for anything but a straight thru exhaust?

What dose it mean if i did a mmufaler mod not to big and the saw runs fine when warmed up but cold start it takes a few choke flashes till its warm.

I just did the mod on the 2511T Echo that all my climbing buddies have done. I took it back to the shop where I bought it and had them reset the tuning. He said he just set it back to the factory settings...It does not stay running in the tree. Huge jump in power, lots of 4 stroking in the cut for the high, so not too worried about burning it up, but not sure what to do. Perhaps I need to get someone to retune it, any ideas?

Most if my experience is with Stihl's 028 (Just playing with what I have). I know of three different style mufflers for these saws, which I believe, demonstrates Stih's attention to the subject. Without a doubt, some concessions need to be made, (spark arrestor, Decibel level, size for example). But when one considers the lengths that Stihl went to, to improve their market share (Internal modifications and re-tooling are not cheap), Stihl would have, for sure, done everything possible to gain horse power by enhancing muffler efficacy (just an external bolt-on part). Can something be gained? sure. Is it necessary on a modified saw? yes, probably more-so than a stock saw. However, I don't think bigger is better. I see some thumbs-down; these most likely come from those who spend and hour randomly chopping holes in the exhaust, but won't spend 10 minutes sharpening their chain. Thank you for the presentation, I think you saved me a lot of grief.

Would you suggest increasing the fuel/oil mix ratio when you increase the size of the muffler mod ? I recently got a Makita 4300 with a catalytic converter , in dim light you could tell was getting orange hot by looking at the outlet hole on the muffler, not good for engine life . I removed the catalytic converter and the saw sounds happier and rpms increased, I don't know how much , it's not a screamer , just sounds like it should to my ear . The manual says to run it with a 50:1 fuel/oil ratio , maybe I should go 40:1 with the cat removed ? The external port is stock , just the internal cat that was removed . Great channel , thanks for sharing a ton of experience.

Makes sense, an unmodified air pump needs little exhaust modification except maybe the noise pollution additions, where an air pump that has been modified to pump more air needs exhaust modification. 2 strokes are a different ball game fuel wise sucking fuel rich exhaust back into the combustion chamber

I have the Husqvarna 450 rancher all stock would it pay to port the muffler or should I just remove the stock baffles

What are your thoughts on thin louvers where the lines are?

How far into the muffler do you insert the exhaust pipe? Do you barely have any of it inside or halfway into the muffler?

What about the Stihl ms261c would you put lil holes in muffler

Some saw mufflers I’ve seen even have catalytic converters in the winch heat up making it even hotter

Hi, Do you know why their is a rattle in the muffler, sound like small screws or washers. My problem is a very difficult pull cord to pull.🤔

If stock, what about removing the arrester only?

I have an old top handle skill saw that is so old the muffler is wide open lol have to be carefull with her she will ignite a dead ash right now

Got a simple question, I heard say that you soldering a muffler mode. You didn't say braze the muffler. Is soldering better then brazing the muffler.

Thank You. I like that you establish reason based on real world usage.

Hi Mr. Nice video. I have det same muffler mod on my 576xpg at. Any thoughts on open up the inner baffel so ther is more space for the exhaust gas?

Great video, I enjoy hearing your thoughts on different topics. If you went with 70-75% of exhaust port, is that for ported? What about stock? Would 70-75% work or be too much. I'm thinking out loud here, the forums mention 85% of piston side port opening and that's good for most saws. Not sure if that's for ported only. Thanks for sharing with us. Be safe.