It is a great honor to be a YT student of Mr. Cameron. Kevin was the best m/c tech magazine writer 40 years ago and has forgotten 100x what I'll ever know. I still have my precious Two-Stroke Tuner's Handbook, too. A well designed expansion chamber can give a -7psi and + 7psi scavenging/charging boost with it's pull-push effect.
I always learned from reading articles in Cycle magazine by Gordon Jennings and Kevin Cameron. I bought and still have my copy of The Two Stroke Tuners Handbook. I actually made seven pipes based on the formula for snowmobiles back in the day.
Wow, that is fascinating information. I had no idea how something like exhaust pipes, which seem so simple, have so much engineering that goes into them. Thank you!
Hey Mr. Cameron I remember your articles in the magazine a ummm well a few decades ago . The good old days roberts spencer laguna seca rides up highway one.
It is amazing the amount of engineering that goes into an exhaust. It's easy to think that the manufacturers just stick some metal on to abide by Euro 3/4 emissions, but a lot goes into the process. However, I can imagine how some limitations in power & torque result in behest of regulations - hence aftermarket products + tuning can gain extra results. Cool video
Glad to see how many that understands perfectly well, what an absolute treasure Kevin Cameron is. In truth, "we're not worthy". His book "Sportbike Performance Handbook" (a wheelieing black zx11 on the cover) gave me way more than I ever can use fully. I'm an engineer (though far from brilliant and not automotive) by trade and I have quite a few books about muscle car related topics and automotive engineering textbooks. In my humble leyman opinion: apart from the factory workshop manual for your bike(s) - you won't need another source to understand and optimize your bike.
I follow your awesome comments full of tecnology like almost 20 years in the Magazíne Cycle World ....Congratullations hoy are the best in año related about 2 wheels technology
Kevin! We want a channel with more precious info like this one.... If you go for a 24/7 live transmission... let me know.. I quit my job and buy all the coffee that is.
naveedaka yes it can. The velocity of the intake charge is so high as it goes through the intake valve that it compresses under its own inertia as it reaches the bottom of the cylinder. If the exhaust is correctly tuned that results in compression occurring in the cylinder even before the valves have closed
HI Kevin, thank you for your great videos! I didn't understand the low rpm flat spot. The first expansion point creates a low pressure wave (due to the change in air impedence at the interface which reflects back the pressure wave with opposite phase) which comes back to the cylinder. This is clear. Therefore the only difference between optimum rpm and lower rpm should only be the timing of when the reflected negative pressure wave arrives at the cylinder. Why would a lower rpm create a positive pressure wave?
yes but it is too complicated to solve on fingers, too much variables (and no shape, than volume and length and with what cylinders to combine if is 421)
Thank you Great video, 4/2/1 is exactly what I need to design for my Lycoming 4 cylinder, IO-360-Turbo inner cooled, horizontally opposed, flat-plane crankshaft, racing airboat engine max rpm is 2650! can you answer my question? Which (2) cylinders in the firing order are connected to the 4 into 2? thanks Richard
hey Kevin ... great technical videos I'm an ASE Master Certified Automotive Technician and an automotive instructor I Just bought my first fuel injected bike and they looked at me strange when I asked to buy a service manual too ... but that's a story for another day My question is ... I bought a 2019 Fury (non-ABS) and ALL the aftermarket exhaust companies telling me I need to buy tuner with their exhausts. However, my bike, while it has a catalytic converter, does NOT have an O2. Therefore, by leaving the CAT installed and just modifying the exhaust baffles, won't the ECM MAP detect and adjust fuel trims accordingly? I started by cutting a 9/16" hole into my baffles and find no negative side affects at this time. The bike sounds better but I want more and am thinking of removing the baffles completely (NOTE) the baffles in the furry are NOT part of the CAT. Thoughts? Thanks in advance Sean
Hope I'm not too late for comments/questions. I acquired a 2001 Yamaha 1600 cc Roadstar. The first owner is a motorcycle mechanic. I'm the third owner. I'm restoring the bike because I suspect the modifications to it may not have been well thought out. Specifically, the first bend in the header of the tailpipe has a crimp in it. Common sense tells me that no matter the dimensions of the rest of the pipe, this crimp narrows the pipe. Could it be that this crimp is intentional in the design and serves a legitimate function? Or, was it the best someone could do on installing cool looking exhausts?
I have a 180° inline twin. The two exhaust runners have a pipe joining them. This is apparently to improve mid range power at the sacrifice of top end power. Why does this phenomenon happen???
A T Same reason, scavenging. With most designs, you’ll only end up moving peaks and dips around(assuming the design wasn’t absolute dog poop in the first place). You may wind up killing the absolute top because scavenging isn’t as efficient at that RPM, but you have a more usable torque curve. You may kill the bottom end, but that doesn’t matter because it’s a race bike and you aren’t going to see 5000 RPM while on track. Your goal is to move the peak in the areas you use more often (resulting in higher average torque) while moving the dips to an RPM range you don’t use much if at all (a Harley isn’t going to make use of a scavenging at 8000 RPM). Or you can develop an exhaust system that makes power nowhere except at the top. This looks great on spec sheets (gains of 20 Hp!!!) but you lose torque (and therefore power) at all other points along the curve, and ultimately wind up with a slower bike. Assuming similar RPM, average torque (aka area under the curve) is what wins in a straight line.
Can you explain why? I have a ninja 650, it has too many bends in the exhaust, Immediately coming out of the cylinder block, while the inline 4 has straight line,
Hello I have a quick question for ya. Love your videos btw! I am hearing a slight clicking noise coming from my engine (Honda grom 2018) any idea what this can be? It seems to get louder after I’m done riding. Love to hear your thoughts 💭
tz750d I can't believe it has been such a long time since ... Enjoy your endless conveying of knowledge as you always did. I for one learned to think differently after so many assumptions were torn down by 1st hand scientific knowledge you offered.
so a negative wave travels back to the piston and becomes low pressure? i dont get it.... in my imagination it is the inertia of the gas comming out the pipe that makes the negative pressure at the piston to make way for incomming fresh charge of fuel and air
I'm pretty sure the 600 header is a 4 into 1 it has 4 primaries going In one collector then out to one pipe a 4,2,1 has 4 primaries into 2 pipes then into one collector
You got the idea old man, but exhaust reversion contaminates the mixture and that's no bueno. Just think about it for a second, if you bread carbon monoxide will help your performance? Ah, before I forget 2t and 4t engines are not the same and not all engines have overlap.
It is a great honor to be a YT student of Mr. Cameron. Kevin was the best m/c tech magazine writer 40 years ago and has forgotten 100x what I'll ever know. I still have my precious Two-Stroke Tuner's Handbook, too. A well designed expansion chamber can give a -7psi and + 7psi scavenging/charging boost with it's pull-push effect.
..born in 1960, I've repsected your opinion through a succesful snowmobil and H2 Kaw bike racing. THANK YOU For your input. PEACE GRD
Huge thank you for killing the jump cuts. LOVE this series, it’s awesome to see people with serious knowledge sharing it!
I always learned from reading articles in Cycle magazine by Gordon Jennings and Kevin Cameron. I bought and still have my copy of The Two Stroke Tuners Handbook. I actually made seven pipes based on the formula for snowmobiles back in the day.
The most straightforward explanation yet, many thanks.
Well that was the best 7:32 minutes I’ve used. Learnt more then than ever before. Thanks.
Same
wow your explanation is very helpful in understanding backflow
That is probably the best explanation video on whole youtube
I remember Kevin and Gordon from the old cycle mag days. Always looked to the articles if nothing else👍
Wow, that is fascinating information. I had no idea how something like exhaust pipes, which seem so simple, have so much engineering that goes into them. Thank you!
Best explanation i have ever seen
No one explained it so deeply
Ajinkya from India
Hey Mr. Cameron I remember your articles in the magazine a ummm well a few decades ago . The good old days roberts spencer laguna seca rides up highway one.
thanks a lot for taking the time to make this video. Its Fantastic.
speed of sound depends on gas temperature , so at 15c it is 340m/s , but at 1000c it is 717m/s
Wow. Fascinating.
That is why the OEM is so imp.
Thanks
I don't know what prompted me to watch this, but I'm glad I did. Absolutely fascinating. Thank you!
It is amazing the amount of engineering that goes into an exhaust. It's easy to think that the manufacturers just stick some metal on to abide by Euro 3/4 emissions, but a lot goes into the process. However, I can imagine how some limitations in power & torque result in behest of regulations - hence aftermarket products + tuning can gain extra results. Cool video
“After engine, exhausts are the most research based component in a motorcycle ".Thnks sir for providing this knowledge
Intake and exhaust, the true dark art of motorcycle design.
Glad to see how many that understands perfectly well, what an absolute treasure Kevin Cameron is. In truth, "we're not worthy".
His book "Sportbike Performance Handbook" (a wheelieing black zx11 on the cover) gave me way more than I ever can use fully. I'm an engineer (though far from brilliant and not automotive) by trade and I have quite a few books about muscle car related topics and automotive engineering textbooks. In my humble leyman opinion: apart from the factory workshop manual for your bike(s) - you won't need another source to understand and optimize your bike.
Beautifully explained. Thank you!
I learned so much from Kevin, and still do. Gracias
I have a small horizontal pipe linking the two middle pipes on my k6 750 suzuki, is there an awesome description of it's purpose available? =)
I follow your awesome comments full of tecnology like almost 20 years in the Magazíne Cycle World ....Congratullations hoy are the best in año related about 2 wheels technology
Now I know something I didn't know before. Thank you
Thats absolutely masterclass
Very cool. Easy to understand.
This music made me feel like I was watching a Harry Potter movie if Dumbledore was a mechanic.
You're a Mechanic, Harry!
Thank you for this explanation! I like that you explained things slowly and in a way that made sense, without using big words or fancy jargon!
Brilliant! Thanks Kevin for these expert words.
Fascinating 🧐 never knew. Thought exhaust was only to quieten noise . Spooky music ,love it
this explains exhaust functions clearly.. thank you
Kevin! We want a channel with more precious info like this one.... If you go for a 24/7 live transmission... let me know.. I quit my job and buy all the coffee that is.
Thanks, I found this fascinating
And that, kids, is why homemade exhausts are a bad ideia!
Paulo Carreiro idea*
That was really cool and easy to digest, thanks !
That background music make me like a kid listening to story tale.
thank you for this video
Very good video, really educational
Waoooo !! Thank you so much never anyone did explained me that
So anything after that pipe doesn't affect performance such as the silencer?
sir..can a tuned pipe in four stroke get the volumetric efficiency above 100%??
naveedaka yes it can. The velocity of the intake charge is so high as it goes through the intake valve that it compresses under its own inertia as it reaches the bottom of the cylinder. If the exhaust is correctly tuned that results in compression occurring in the cylinder even before the valves have closed
What are good references for exhaust tuning math?
This is where "tuned length headers" come from? ...how do they work out the correct length for the "tuned length headers"?
Fantastic explanation
My zx9r gets buzz thru bars and pegs.ive checked almost everything. Could it be something to do with exhaust pressure. I think I have 4-2-1
The music! Do you know Bill C in Corona Calif? Bill's Pipes
Had not considered the negative pressure wave... Danke :)
Mechanical Guru. Thankyou master.
Amazing as always.
Could you add the cone collector to the 4-2-1 header for more scavenging??
Nice video, thank you for sharing
HI Kevin, thank you for your great videos! I didn't understand the low rpm flat spot. The first expansion point creates a low pressure wave (due to the change in air impedence at the interface which reflects back the pressure wave with opposite phase) which comes back to the cylinder. This is clear. Therefore the only difference between optimum rpm and lower rpm should only be the timing of when the reflected negative pressure wave arrives at the cylinder. Why would a lower rpm create a positive pressure wave?
because max negative pressure is pointed on some high rpm, so it is logic that on some lower rpm is opposite situation
So this means removing the decibal killers makes no difference then since it happens in the beggining part of the exhaust. Am i right?
Is there any formula for certain cylinder volume and/or RPM to calculate proper exhaust pipe shape?
yes but it is too complicated to solve on fingers, too much variables (and no shape, than volume and length and with what cylinders to combine if is 421)
Thank you Great video, 4/2/1 is exactly what I need to design for my Lycoming 4 cylinder, IO-360-Turbo inner cooled, horizontally opposed, flat-plane crankshaft, racing airboat engine max rpm is 2650! can you answer my question?
Which (2) cylinders in the firing order are connected to the 4 into 2?
thanks Richard
aim those with longest timing between spark , to get max power on high rpm
hey Kevin ... great technical videos
I'm an ASE Master Certified Automotive Technician and an automotive instructor
I Just bought my first fuel injected bike and they looked at me strange when I asked to buy a service manual too ... but that's a story for another day
My question is ...
I bought a 2019 Fury (non-ABS) and ALL the aftermarket exhaust companies telling me I need to buy tuner with their exhausts. However, my bike, while it has a catalytic converter, does NOT have an O2.
Therefore, by leaving the CAT installed and just modifying the exhaust baffles, won't the ECM MAP detect and adjust fuel trims accordingly?
I started by cutting a 9/16" hole into my baffles and find no negative side affects at this time.
The bike sounds better but I want more and am thinking of removing the baffles completely
(NOTE) the baffles in the furry are NOT part of the CAT.
Thoughts?
Thanks in advance
Sean
So, can a catalytic in a stock pipe cause positive pressure back into the cylinder at high rev?
Great video series Kevin ! Do you still ride sir and if so which bike currently ? Thanks
That music tho...
Hope I'm not too late for comments/questions. I acquired a 2001 Yamaha 1600 cc Roadstar. The first owner is a motorcycle mechanic. I'm the third owner. I'm restoring the bike because I suspect the modifications to it may not have been well thought out.
Specifically, the first bend in the header of the tailpipe has a crimp in it. Common sense tells me that no matter the dimensions of the rest of the pipe, this crimp narrows the pipe. Could it be that this crimp is intentional in the design and serves a legitimate function? Or, was it the best someone could do on installing cool looking exhausts?
What happens if we install 2 stroke pipe in a 4stroke 125 cc mopped engine?
I have a 180° inline twin.
The two exhaust runners have a pipe joining them. This is apparently to improve mid range power at the sacrifice of top end power.
Why does this phenomenon happen???
A T Same reason, scavenging. With most designs, you’ll only end up moving peaks and dips around(assuming the design wasn’t absolute dog poop in the first place). You may wind up killing the absolute top because scavenging isn’t as efficient at that RPM, but you have a more usable torque curve. You may kill the bottom end, but that doesn’t matter because it’s a race bike and you aren’t going to see 5000 RPM while on track. Your goal is to move the peak in the areas you use more often (resulting in higher average torque) while moving the dips to an RPM range you don’t use much if at all (a Harley isn’t going to make use of a scavenging at 8000 RPM).
Or you can develop an exhaust system that makes power nowhere except at the top. This looks great on spec sheets (gains of 20 Hp!!!) but you lose torque (and therefore power) at all other points along the curve, and ultimately wind up with a slower bike. Assuming similar RPM, average torque (aka area under the curve) is what wins in a straight line.
Can you explain why?
I have a ninja 650, it has too many bends in the exhaust, Immediately coming out of the cylinder block, while the inline 4 has straight line,
Mostly aesthetic and packaging
I have that book. Gordon was my godfather.
I thought the exhaust sound waves travelled at 500m/s, gas speed was closer to 125m/s?
Hello
I have a quick question for ya. Love your videos btw! I am hearing a slight clicking noise coming from my engine (Honda grom 2018) any idea what this can be? It seems to get louder after I’m done riding. Love to hear your thoughts 💭
Maybe it's because the silencer is stretching after its very hot
Thank your sir.
tz750d I can't believe it has been such a long time since ... Enjoy your endless conveying of knowledge as you always did. I for one learned to think differently after so many assumptions were torn down by 1st hand scientific knowledge you offered.
this is amazing.
You are wise!
We are not worthy.....
Thanks subscribed 😁
Love it!
I love it
!
so a negative wave travels back to the piston and becomes low pressure? i dont get it.... in my imagination it is the inertia of the gas comming out the pipe that makes the negative pressure at the piston to make way for incomming fresh charge of fuel and air
MunsKi yeah, I thought the same... sounds like a load of hot air
Munski except physics is reality, and your imagination is just that
Aaaaand now my search for after market slip on exhaust has become more complicated and expensive.
nice work... i made exhaust too
amazing
genius indeed
Car engines, commercial and agricultural and even engines do this too, as the makers want to be able to advertise how efficient their own product is.
I'm pretty sure the 600 header is a 4 into 1 it has 4 primaries going In one collector then out to one pipe a 4,2,1 has 4 primaries into 2 pipes then into one collector
Watch again. He explained that.
old man bet you were a player at age,nice informative stuff thou!
Is this why funny cars use mufflers? LMFAO
So, back pressure IS desirable.
You got the idea old man, but exhaust reversion contaminates the mixture and that's no bueno. Just think about it for a second, if you bread carbon monoxide will help your performance? Ah, before I forget 2t and 4t engines are not the same and not all engines have overlap.
Daytona with a 4 cyl engine??🤔🤔 Did I heard that right🙄🙄
When he was *IN* Daytona....
This is why making your own 2stroke exhaust is probably going to hurt performance.
👍👍👍
Get rid of background music. What's the purpose of it? To make the perception of your narration even harder?
:gobsmacked:
Great video spoilt by the soundtrack. That 'music' is like the f^^king Chinese Water Torture- pleeease make it stop!
Bull shizzle. The muffler is designed that way to cut down on noise.