How To Port A Chainsaw! What Is Blowdown? Basic Porting Explained! Finding Peak Power! Muffler Mod!

[@donnywalker4691]

Great video bud keep it up

[@Smittyschainsaws]

I’m honored! Thank you!!

[@kennytheguitarfanatic054]

This is one of the best videos on porting chainsaws I have seen !

[@Smittyschainsaws]

I'm blushing!

[@jumpunjak]

Good j job

[@davidarford4420]

Can't believe I missed this one. Absolutely the best explanation I've ever heard of blow down and peak power and torque by far good video especially for somebody that really doesn't know much about it. Great job Smitty👊👍👍

[@Smittyschainsaws]

Glad it was helpful!

[@justinweaver8787]

Great way to illustrate how it works i understand a lil more now!

[@Smittyschainsaws]

Sweet!

[@Finom1]

Bless you Smitty, for sharing your wisdom with your loving community:)

[@Smittyschainsaws]

Thanks buddy! You always leave great comments!

[@walt5797]

And the penny just keeps dropping. best explanation yet for my understanding, Thanks Smitty. I'm glad I watched this before I started grinding.

[@crazyfeller5704]

Good stuff. I had a revelation several months ago regarding exhaust shape- similar to the shape you noted. I read that it is better to widen the top a bit, before the transfers open- made total sense.

[@Smittyschainsaws]

Glad you enjoyed it buddy!

[@danwerkman]

I have been trawling YT for chainsaw porting videos and I am sorry to say most of them are all about the person not the subject. So much self praise about themselves. Really enjoying the information your sharing. Instant Sub

[@Smittyschainsaws]

Thanks 👍

[@KentuckyFriedFixes]

Great stuff! I enjoyed every second of this. More please. Thanks Smitty!

[@Smittyschainsaws]

Working on it now buddy!

[@dennisjensen6142]

Great video Smitty. The drawing really helped

[@Smittyschainsaws]

Thanks buddy!

[@harrybrandt2462]

Love it Smitty Good info for my simple mind...

[@Smittyschainsaws]

Thanks buddy!

[@4seasonpursuits724]

One of the most informative porting videos! Thanks for sharing your perspective and easy to understand.

[@Smittyschainsaws]

Glad it was helpful!

[@alanreynolds2125]

Good job Bri, thanks

[@Smittyschainsaws]

Thanks buddy!

[@travisgauwitz8684]

Great video professor Smitty

[@Smittyschainsaws]

Glad you liked it!

[@drd1924]

Oh wow, your explanation here is great!, especially explaining angling of the tops of the transfers

[@shakdidagalimal]

That was well done.

[@jamesmooney5348]

Tinman's saw cut in 1/2 is a great tool as well. But your explanation is very good. I'd like to hear more of your knowledge. You teach in a way, I can visualize what's happening. Thanks

[@Smittyschainsaws]

Thanks buddy!

[@coolestguyontheplanet723]

Love the pictures 😊

[@MrSprintcat]

Good pictures 😊

[@ljurhallabocken]

crankcase compression only reaches like 10 psi. If you think about the engine running at 50-250 revolutions per second or 3000-15000 rpm, think about how long the transfers are open for each stroke. If you have an air hose pressurized to 10 psi, and could open the gate for 1/50th of a second, and that is a full stroke of the engine at idle, how much air is coming out of that hose? The only way these engines can pump efficiently is from the energy produced by the burning mix. At first the expanding gases push the piston down, then as the exhaust opens and the gases hit the muffler can and expand, it created a pulling effect on the rest of the cylinder, vacuum. And a lot of it. So the transfers want to open just as the pressure is changing to a vacuum for the most efficiency. After pondering this for a bit I see this as the only way to get enough transfer to run the engine. The crankcase compression combined with a vacuum on the other side means the transfer port sees a much greater differential than just 10 psi to atmosphere

[@Smittyschainsaws]

Now start looking at tuned exhaust systems. The push pull effect gets amplified!

[@ljurhallabocken]

@@Smittyschainsaws yes, I have build a couple of tuned pipes for my race saws.

[@Smittyschainsaws]

@@ljurhallabocken Amazing!!

[@jamesmooney5348]

This video is great. Thanks

[@McCullochMac6]

I think you explained it fantastic...Helped me alot..

[@Smittyschainsaws]

Glad it helped!

[@wyliecoyote1]

Very interesting video. I don't know a lot about it, I wonder if an experiment would be to install a pressure gauge where the decompression valve hole is. See what those ignition pressures are, how it drops off on exhaust stroke. Maybe not.

[@guymansford7123]

Thanks so much. That really made something that had confused me really clear. Best wishes from UK.

[@dennisthemenace57]

Excellent, thank you

[@brycestewart9493]

Love the video smitty !

[@treebender261]

I thought is was a good explanation it's nice to have people try to help with DIY chainsaw porting it seems more channels are going that way a few years ago it was tough info to get ahold of but with social media paying off well for those who get the subs we all benefit thanks smitty I found a Yamaha blaster pipe in my ATVstuff not sure if it's a 125 or 200 cc expansion chamber hit me back if you could use it on the 925

[@Smittyschainsaws]

Heck yea!

[@treebender261]

It was a new take off so it's nice I need to get you a pic I can cut it down for you and weld it up how do I connect Facebook?

[@Smittyschainsaws]

@@treebender261 Facebook or email will both work.

[@gustavogartner3145]

Hola....yo creo que a más purga...más importante es la sintonización del escape...un abrazo

[@_ZUNG_]

This is great info. Thanks mate

[@Smittyschainsaws]

Glad it was helpful!

[@bryanmarks4070]

Great video. Are there go to numbers rule of thumb to improve saws performance. In 70cc and 90cc saws. Long bar work saws.

[@Smittyschainsaws]

Usually you just don't make drastic changes. The longer the bar the less aggressive you get with raising the roof.

[@bryanmarks4070]

@@Smittyschainsaws thanks. I try and stay around 100 on the exhaust and 76 on the intake. I don’t have a lathe yet. It’s on the way as well as a 90 degree tool for the transfers. Thanks for the reply!

[@Ирокез]

Hi. Could you explain why on chainsaws the crankshaft is shaped like a “pear” and not a full circle? Wouldn’t a round crankshaft increase the transfer pressure? After all, there will be less free space - on motorcycles it is round.

[@Smittyschainsaws]

Yes you are correct but the largest gain from full circle cranks is very wide power band. Chainsaws don’t really need that wide of a power band.

[@Ирокез]

@@Smittyschainsaws Thank you! You are the first to clearly answer this question.

[@kowski9477]

Your way of explaining is easy understanding and yes with making more videos sharing your knowledge. I'm looking to put a McCulloch 7-10 auto piston and cylinder on a 450 Husqvarna chassis with some kind of bottom end. You and others may be thinking " WHY" and to that I say " WHY NOT" with no rhyme or reason other then the parts and pieces with pieces of parts are there.

[@Smittyschainsaws]

Awesome, thank you!

[@galipan6213]

Excellent, thanks+++++++++++++

[@patrycklealoliveira8106]

Hello from Brazil my friend Can you try to help me, please? My chainsaw(chinese) has a problem with excessive compression. But when I remove the spark plug the piston rotates normally. Even placing your finger in thze spark plug opening causes the piston to become extremely compressed again. Yesterday I installed a completely new cylinder and piston, but the problem remains. I changed the spark plug, removed the carburetor and exhaust fan, and still the problem remains. Do you have any idea what it could be? Can I send you a video showing the problem? I have been seeking help with this mystery on various social media channels, Instagram, KZbin, but no one has been able to guess what could be causing the problem.

[@Smittyschainsaws]

Send video. Nighthawk68mag at g mail

[@kowski9477]

GREAT SIMPLE EASY TO UNDERSTAND VIDEO! THANKS

[@Smittyschainsaws]

Glad it helped!

[@brycestewart9493]

Love the video smitty !

[@Smittyschainsaws]

Appreciate it!!