If you ride a dirt bike, you most likely have a 2-stroke, especially if you do Enduro. However, it is also likely that you don't fully understand how your bike works or why it has certain parts. For example, have you ever wondered why the exhaust pipe, one of the most important parts of the 2-stroke bike, is shaped the way it is?
If you haven't, here's your chance! After this video, you'll understand perfectly how it works, the reasons behind its shape, and how it affects the performance of your bike.
Enjoy and subscribe to know more about the bikes we love to ride!
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Cheers!
#ExpansionChamber #2Stroke #ExhaustPipe
Thank you all for the love you have shown, I really appreciate it! 😊Note: No, I did not mention the first back pressure generated when the pressure wave reaches the divergent, which is responsible for creating some suction on the crankcase. I left that info out to make the video clean and simple (so everyone can understand it without being intimidating) and focus on the main pressure wave generated on the pipe!
Thank you so much mate!! 💪💪
You have done a great job mate spread the 2 stroke genius 👌👌👍👍🇬🇧🇬🇧 love from England 👍👍
@donnie baker you have it exactly right, when your power band as people like to call it is kicked in and you're flying your pipe is at full capacity ! Max flow
Thank you so much! I really appreciate the comment! 🙏🙌🙌
@Richard Key MZ
Esse sotaque portugues nao engana ninguem ahahah. Subscrito! Adorei o conteúdo e a explicação direta ao assunto.
💪💪💪
Not even sure why I watched this lolz! Know how 2 stroke pipes work already. But I have to say this guy did a really good job. You just made a few people a tab bit smarter. Could you imagen if this guy used cards with pictures on it.... All these kids after 2010 would actually learn something then LOL!
Thank you sooooo much for that! Im glad I could teach you something, you just made my day 🙌🙌
the best explication.
Thank you! 🙌🙌
Evem zlatan doesnt know he is on youtube talking about two strokes.
🤣🤣🤣
Coincidentally, these same animations can be used to explain what happens when I eat chicken nuggets.
😂😂😂
What about the end of the pipe? What effect does stinger length have on performance? I wanna make mine a little shorter on my RZ350 LC.
Bray brap for life
Amen for that!
So a 2stroke like uses backpressure to create a the powerband.
Very intresting.
some racing 2 strokes have completely straight pipes , no bends :)
Can you explain the "Stinger" size. Length? Diameter? Effect? Etc?
Yes I can, and I will!!
Ótimo vídeo meu caro! Reconheci seu sotaque português de cara! Um abraço do Brasil!
Muito obrigado Rafael! 🙌 um enorme abraço de Portugal! 😊💪
My question is why 2 stroke is better for enduro than 4 stroke ....... explain with more animation and its science .more deeply.
Ok this definitely makes sense to me as rc engines have a tuned pipe as well. The nitro rc engines run as normal from idle to about half throttle and when you wide open them they really scream almost like you hit the nitrous switch. My question is why don't 2 stroke equipment have these tuned exhaust and is there any real gains to muffler modifications or would this be damaging to say a chainsaw or trimmer?? In the landscape world more power is generally a good thing but not if the cost is a peice of equipment with a lot shorter engine life.
Maybe its worth mentioning that this design were invented by east german engineers at MZ factory, later stolen by a MZ engineer who fled to the west and sold the stolen invention to Suzuki, now spread across all brands.
You confuse pressure with speed, when the pipe becomes bigger, the pressure raises and when it becomes smaller, the pressure drops. Venturi equation
The fluid must remain at the same temperature throughout the flow
@Steps to Podium which one??
Venturi equation does not apply here since one of its premises is not met
Parabéns pelo conteúdo!
Muito obrigado Rafael!! Grande abraço 😊💪
Nice job.
💪💪💪
ZLATAN!?!?!?!?!?!?!!!!! nah fr, you look dam handsome ...no homo
🤣🤣🤣🤣🤣🤣🤣 thanks bro 👌😂
I lernt something . I love motorbikes !
finally i find video that expalins why twostroke engine exhaustpipe looks so weird. i neber kknow that before so thankyou. when i was young i dirive many different mopeds some have normal exhaus pipe and some have that kind of pipe you show us and we called them powerpipes and we do not even know why or how it gives more power 😄 some times i even think it.s give more power because it,s thicker than normal pipe althought the end of the pipe was not thicker at all and then we make power mufflers just taking out all things that are inside the muffler and and we think no we get more power although we get only more noise and maybe stupidest thing we do was to take whole exhaus pipe off and if im right like tthe motor makes less power and more noise and nothing else but we was kids and have mopeds so it,s almost have to try to tuning it faster. best tuning was change the chain gears that way we get the mopeds accelerate faster but stop speed got lover of course but it feels faster.
Glad i could help! 💪💪
In short a technical pulse generator that can be tuned for specific rev ranges.. been there done that..
Boa Diego ensina nos! - super enduro na veia! ae Diego estive pensando em criar tipo um "segundo estágio" ao longo do caminho dentro ou fora do escape ainda não decidi, o que vc acha que aconteceria, será que ia melhorar um pouco a eficiência da queima do combústivel reutilizado ?
fiboth.info/like/videot/eXltdX7UscqvdJ0
Erm, pressure increases as diameter increases, velocity increases as diameter decreases
🤣🤣🤣
Yeah but I never met this Bernoulli fella. He was prolly just joking.
erm, this is not the Bernoulli equation..
Thank you! That was really clear and made it simple to understand. I once built an exhaust pipe for my 2 stroke and it wasn't easy! There was a very good book on improving 2 stroke performance and the exhaust pipe was a huge part of that. Sadly, I lost that book somewhere along life. :(
Im happy to hear that! I bet it wasn't but it sure was a good challenge, I imagine 💪
There's even more going on with the waves in an expansion chamber. Read the two stroke tuners handbook it's explained better and much more in detail than this.
@Steps to Podium I think you could've quickly showed and explained more maybe without messing with flow graphics. You can't quickly detail pv tech, but can mention they also affect compression and how expansion chamber diameters(even on the same engine) affect power or compression curves. I'm assuming viewers are mostly interested in the really shapely dirt bike pipes you show. Thanks for the vid.
@Steps to Podium The book is out of print, so you'd have to borrow it from a real bike mechanic or pay good money for a used copy now. How would you know that "most people" find books intimidating? Because you do? Are you a slow learner? Did you fall on your head too much? That's ok. Books have no time limit - take your time and read slower. Get over your fear of books and quit dumbing people down to your cartoonish knowledge level. From the book's google description; "Gordon Jennings' Two-Stroke Tuner's Handbook was written in the early heyday of two-stroke, motorcycle road-racing, drag-racing and motocross. This book, now long out of print, was the "bible" of two-stroke performance engine builders and racers and it's a treasured addition to any mechanic's library." And I'm glad you're "happy for me" you condescending PUTZ!
Dude, take a chill pill... if you have read something, I'm happy for you. For those who don't, this video is a damn good way to understand what most people find intimidating to look up in books.
@Steps to Podium Defensive? Some people do understand how their 2-stroke bike works, and you only need a 5 min video to explain what an expansion chamber does if you actually know what you're talking about. And you don't. The "Two-Stroke Tuner's Handbook" is not an "engineering book". I got my copy 40 years ago. Maybe the idea of reading a 1/2" thick book scares you, since you equate it to "the existence of mankind in detail". You obviously haven't read it. From your description; "After this video, you'll understand perfectly how it works, the reasons behind its shape, and how it affects the performance of your bike." That's some BS! And Anonymous wants his face mask back.
Oh, sorry, i didn't know you were expecting that a 5 min video could replace the depth of an engineering book... Next time Ill do a 6 min video explaining the existence of mankind in detail 🙄🤦🏻♂️
check my channel to see how you can increase compression
Very informative and explained great. Thanks!
Thank you for watching! 💪💪
Two stroke pipes are called tuned expansion chambers been in the game for some time 😂
Does the silencer affect the performance of the engine?
@Steps to Podium okay thanks man maybe I'll change my plan
It affects a lot! It's hars to explain you since there's a lot to take into account. I would recommend you to do a deeper research into this subject 💪
@Steps to Podium I am planning on building something using 2 stroke engine but I need the exhaust away from some parts, I'm planning to extend the length of the pipe before it reaches the "bulk part" of the pipe or the divergent... does this affects the performance too? In what way?
Decreases horsepower but can increase torque, depending on the lenght of the silencer
@Steps to Podium does it lower the performance?
very good explanation. thank you.
Thank you for watching!! 💪💪
I hate 2-strokes. They sound and smell horrible and are often unreliable. My hedge cutter, leaf blower and strimmer are 4 stoke
MIT teachers smell exhausting fumes
This was a great video.
Thank you so much!! 🙌
no explanation as to why return pressure wave pushes gases but rebound wave does not but definitely captures the essence of it
Well explained. Thank you.
Thank you for watching! 🙌
Are thows pipes like a Cadillac Converter
Zappa goes technical! Well done, thanks for sharing.
Thank you for watching! 💪
Tenho 100% de certeza que o narrador é Português. Não faço ideia do porquê, sotaque juntamente com tom de voz, acentuação e ênfase verbal talvez ou se calhar todas essas coisas juntas, só sei que sei.
É estás 100% certo! Bom dia alegria! 😂
I still don't get how the pressure wave bounces back, but does not interfere with the exhaust gas...
That's exacty it 👌
@Steps to Podium every pressure wave pushes something away, in this case it initially pushes the air in the exhaust away and pulls the exhaust gasses out of the exhaust. So far to good. But when the wave in the exhaust bounces back ... the only way for that wave to make it back from the exhaust to the engine would be if it's stronger than the next wave outwards. That's the part where I get stuck. But it must probably be calculated and timed in such a way that the 2 waves don't cancel each other out. Amazing technology it is :)
The pressure wave is just the concentration of matter in the air and the exhaust gas is the matter. I even gave an example to try to help understand the phenomenon 😊
So the term "on the pipe" makes perfect sense.
Very educative video. Thanks
Thank you for watching!
i didnt even know this was a thing but its actually really interesting
Glad you found the video interesting 🙌💪
I thought it was a medical model of the lower duodenum
🤣🤣🤣🤣
Thanks. How does exhaust shape affect the power valve? Another video in the making?
Yeeeeeeessss
what about the scavenging effect???
I'm going to talk about it on another episode! 😉
Great video! I learn something new everyday!
Fun fact: The high pressure wave is actually a sound wave which is used to force the unburnt mixture back down into the cylinder, this gives a slight positive displacement effect like turbocharging. Darn awesome 2 strokes!!!
@A Kent alright then so my idea of it was right. Awesome! Thanks man👍🏼
@Roman Bernal this is basically what causes the power band effect, as the revs increase the power increases.
So like ..in what way would that affect the powerband
Just installed a short-straight pipe exhaust, I can tell it's faster cause its louder Yeeeeee whoooooo
Von braun
Nice. Clear and concise.
Thank you for watching!!
Latin English, feio d entender....
😘😘😘😘
Tava na cara o que era.... O complexo do vira lata!
Ui, desculpe realeza britânica 🤣
Trehunder cc
Wow! If only people could use sound logic like this when thinking Earth is a spinning water pear in an infinite vacuum... LOL
Check out what happens when you restrict the stinger pipe at the end (exhaust gas outlet) with different diameter flow restrictors (washers).
nicely done. 2 stroke engines have about a 6:1 compression ratio once you figgure the ports in.... Timed Area Per Unit of Displacement... explain this next please!
I ice raced Mercury sno twisters in the mid seventies and the pipes on those machines where never duplicated. Mercury even had Tipsters as modifications to enhance rpm. How to cut and shorten for a given rpm. Very high tech at the time. I believe it was Les Cahoun that developed those pipes. A talented 2 stroke engineer that ended up at OMC in their engineering room. A book called 2 stroke tunrs handbook was our bible in the racing days of design and mods. Cool stuff !
Ypvs
Wow, excellent video!! Thanks for making it!!
Thank you for watching!! 🙌💪
It's called an expansion chamber.
People love two strokes because they make hella power ALOT cheaper. Point blank.
In early days the exhaust pipe was also referred to as an “ extractor” and the smaller pipe at the end was the “stinger”. M/Cs sometimes came with narrow stinger openings to get more horsepower but it caused the power to fall off at low rpm so commonly the stinger was widened in diameter to get power at lower rpm and prevent a bike from ‘falling off the pipe” or losing power. There were no silencers when I stated racing.
good information too bad you didn't show the picture of the early Honda Elsinore it's how their pipes used to run underneath the bike frames
Suzuki had those too. It worked great on a track not so great on the trail.
How can the gasses travel at the same speed, when the cross-section gets ever larger? Should they not be slowed-down to keep the flow constant?
Your looking at it with the Bernoulli equation in mind, but in this case it doesn't apply. 😉
Very nice
in what world is the two stroke getting more popular? -- they are all but phased out - even 2 stroke scooters and chain saws are starting to disappear
That's why 😂
@Steps to Podium nope- the USA -- we haven't had road or trail legal two strokes since the 1980's lol
You're not from either Europe, Austrália or South Africa, aren't ya?😁😆
спасибо мужик
A good explanation to the black art of two stroke exhaust pipes.
Thank you for watching! 😊🙌
It's really crazy to think, how just change the exhaust system can completely change both the power and the torque in the 2 stroke engine
Only half the story
I think i have a solution to the pipe dent problem, just put a damn metal bar around it.
2 strokes really shine in snowmobiles, where some snowmobiles make 180+ hp while weighing only around 500lbs, and that’s stock. Mods can increase the power to weight to a ridiculous level.
yeah it just bounces back ... its that simple.
The YPVS really helped the RZ 350s get some low end torque, and with a set of good pipes and pistons and reed valves and head work you could fly.
Walter Kaaden was responsible for the tech originally which came directly from the development of the V1 pulse jet flying bombs from WW2. Fascinating story
sorry, but per Bernoulli's eqn, the larger pipe the higher the pressure & lower the velocity. The smaller section is the opposite, lower pressure but higher velocity. PV = PV Seems counter intuitive, but that's the physics
You're right, that's how the Bernoulli equation works! But the Bernoulli equation doesn't work in this case since one of its conditions is not met: in this case, the temperature of the fluid is not constant and cannot be considered constant because there is a tempersture amplitude too big from the moment the fluid leaves tbe header to the silencer 😉
Excellent explanation. I've been wondering about that forever.
Glad I could help! 🙌🙏💪
It doesnt raise compression, or at least that is not how it maximizes performance.
Just changed my power bands on my bike. So fast now!
It’s the other way around , in the diffuser (widened) the static pressure rises . In the Jet it gets lower and the speed rises !
The question is, why the fuck is it so loud ?
Because BANG BANG BANG BANG BAAANGA BANG BANG BANG
Superb
Yeah I get that makes sense no?
Well ofc it does or your bike wouldn't start
So what exactly would happen if I tried to ride my 125 with no exhaust. Obviously it’ll be the loudest thing ever but what would I not have sufficient compression for powerband up top?
Yuuuuuup
@Steps to Podium and crazy damage
Yes!
brilliant lesson
Thank you for watching!
Le sigo desde Colombia
Gracias tio!!🙌🙌💪💪
Thanks we'll explained
Thank you for watching! 😊💪
So what about making a bike with YEIS bottles (volume before/after the carb, Power valves, tunable volume outside the exhaust throat... and a movable cone (like a funnel) shadowing the convergence, inside the expansion chamber so it can be tuned to the revs.... You could even run a U in the header pipe before the divergence like a trombone so you can tune the timing of the gas there...
Just subscribed and I am looking forward to digging into more of your videos! Turning 60 this year means nothing to me, I have four 2 strokes, two enduros and two trials, and I feel like I'm 40! But I have no problem learning from younger people and you clearly know what you are talking about! Thank you for your commitment to providing such good information! Blessings from Colorado!🙏
Thank you so much for your comment and nice words!! I really appreciate it and I hope to see you around in thr comment section! 😃 Let me hear more about what you think about the videos 💪
Thanks for the video. it was great. However, I have 1 question. Why is it necessary for the for the exhaust to go back and build pressure? Does it create more power, less power....what is the actual reason and would it do to the engine performance? Thank you
Thanks! The goal is to supercharge the engine!
nice video, thanks !
Thank you for watching!
I think hard enduro sucks
Bro good video
thanks! I appreciate it 😊
So if it helps add compression, would doing a compression test with your pipe off give incorrect results?
Yes!
Good explanation thank you. Does the length of the tailpipe affect the power/performance please? I have a motobecane 99Z engine.
Why not, try and see what happens 😂
@Steps to Podium No just the long 1 inch pipe there is no silencer just the expansion box which can be exited at the side of the car.
You mean the silencer?
@Steps to Podium Thank you, We have a 50cc Motobecane 99Z engine in a little French car, I fitted an expansion chamber exhaust then a 1 inch pipe to the rear of the car about 3 feet long. With two persons you can feel some torque, I wonder about removing the pipe?
Thank you for watching! :) Yes, it does! A smaller tailpipe increases peak power and a longer tailpipe increases torque.
Although it's counterintuitive, according to Bernoulli equation when the gases leaving the engine first encounter the increase in diameter at the beginning of the muffler, the velocity does slow, however, the pressure Increases (not decreases, as mentioned in the video).
@Steps to Podium Bernoulli's principle is a simplified model for conservation of energy. It's also for incompressible fluid, but that doesn't change the fact that your theory is backwards: dynamic pressure drops, static pressure increases. It's the pressure wave that you need to focus on, not the volume flow (Bernoulli's principle is helpful in understanding the pressure changes of the volume flow which affect the pressure wave, but isn't the only theory you need to apply)
Bernoulli equation does say that, but a condition for the bernoulli equation to be valid is that the fluids have to be at constant temperature, which does not happen in this case 🙂
I wondered for many years thanks
glad I could help! thanks for watching 😊
I have a Polaris trailblazer 250 it’s a 2 stroke is there an exhaust that will make it sound better??