Comments by "EarthSurferUSA" (@EarthSurferUSA) on "driving 4 answers" channel.

We learned with 2-stroke Motocross, to always keep a finger on the clutch lever to help control abrupt power. Even with 50 hp, on corners with good traction, we would pull in the clutch while entering a corner, pin the throttle open, and feed the power out with the clutch. That would even let us enter the corner a gear higher than normal, (which also taught us faster corner speed), and not have to shift up again after the exit. The technique was developed by Kent Howerton in the 70's, to keep his Huskvarna competitive the the new and faster Japanese bikes.
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Why do we call human advancements "crazy" when they work in reality? It was not that long ago when the Wright brothers were called "crazy". "Thinking" (figuring out reality the best we can), and "crazy" are 2 vastly different things.
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Here is another way the 2-stroke and 4-stroke differ, at least with Motocross bikes: When people with some free enterprise in their hands created the 2-stroke engine for Motocross bikes, say starting in the early 60's I believe, the cost of a dirt bike went down, (and I bought 3 of them as a kid making $1.00/hr at my Dad's store at the age of 10-16, in 1974-1980). But when a dictatorship like the EPA forces the 4-stroke engine on the MX industry, the price almost triples again, (the first time is a similar story of intervention of free enterprise.), and not many people are affording them anymore. The bike I bought for $800.00 as a kid, can not be afforded as a kid today at 10 grand. There is another difference between the 4-stroke and the 2-stroke for MX, and it is the same difference between communism and liberty.
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You forgot the most important/valuable aspect of teaching,-----------------his knowledge. That sir, trumps all other entities that you mentioned. But you are right he can teach a class full of teachers with it, and if he taught your class, you would not have missed the most valuable aspect of teaching. :)
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@fhe3220 Look at a infant child's face smile, when they figure something out. Figuring stuff out is fun, and it is human to do so. :)
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You just learned from somebody who knows what he is talking about, (rare today). This man is an example of how mankind should be IMO. He does not think with his skin color or genitals as taught in our schools today. He thinks with his brain, and we get good at that too if practiced.
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@scottamolinari Maybe racing/factories should create it's own management, and drop these outside "rule makers" who hinder the real progress of mans mind.
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A bigger disk diameter for more powerful braking is not really about more surface contact, but the pad contact being further from the center of the hub, so it is a longer lever, and does greatly increase stopping power,---if the tires hold the road surface. The flip side is heat. More surface speed is had by the bigger disk, (more distance around the circle for the same rpm.), so it will generate more heat. All coefficients of friction being the same, the amount of heat developed, (before dissipation), shows the braking power nicely. But the friction of the tire on the ground has to be more than the braking so the tire does not lock up. So wider tires are used for applications of aggressive braking, (racing). From different road surface condition, (from ice to dry clean pavement), different tires and different braking systems, to say the tires are the difference and not the brakes for distance is a bad statement. I am sure many car tests were dine with similar car weight, the same tires, and different performing brakes, (the only factor of difference), and if all the tires don't skid 100% of the time when braking, you will have different stopping distances.
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My goodness!! Your spelling is terrible. :)
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@chrispy1965 "As a teacher myself makes me wonder the following question, what makes you think that teachers dont already practice this?" Your results. How is your math sir? Because I know the kids today have a hard time counting change, knowing cursive writing and reading an analog clock. How about we stop thinking with our skin color and genitals, and use our brains again? The results sir. That is how we know our education today is failing our citizenry. It is a sabotage of mankind. How "progressive".
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"receive power or transmit power" I think they all do both at the same time.
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Compression is adjusted by head volume, (trapped volume), with the valves closed. I don't know what "clearance volume" is. I never heard that term before.
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What would stop you?
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"Perpetual energy" has been a dream for centuries I am sure. It has never been done.
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You do a pretty good vid IMO, (much better than most on YT.). What is your background? I bet you did not waste your brain with a gender studies degree. lol
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I don't think "inventing something" requires that you invented everything about the invention. For example. Robert Kearns, a electronic professor in Detroit Michigan invented the intermittent windshield wiper motor. The auto companies stole it from him, (which he won in court many years later), and part of their argument was that "he did not really invent it, because he used electronic pieces that you can get from a catalog." If you ever see the movie, "Flash of Genius", it is the story about him, and the justice he finally received, (we are suppose to have "speedy and fair" trials in the USA.). It was interesting how he tore that argument up in court, in the movie.
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The inventor is the person who made it work. Everything else is poorly made in china. :)
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I think there is also a great relationship between the early gas engine, and the manufacturing techniques that we also evolved in order to make them. Machine tools for example, also had to be made and new cutting tools had to be evolved. I learned that HSS cutting tools, (High Speed Steel, what most drill bits are made from today), was developed by a guy named Fredricks (?), and HSS was so much better than what they were trying to use, it made all the metal cutting machinery obsolete just about overnight, and new machinery had to be developed. The later jump to carbide cutting tools, we were much more ready with, and they came out about the same time when better machines were needed for them. "production or poverty" Always was, always will be. :) You do a good channel and it is nice to see. Doug in Michigan.
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There was a dirt bike (motorcycle) called the "ATK" developed by Horst Lietiner. He mounted a smaller diameter rear brake dist on the counter-shaft sprocket shaft (front sprocket). The small dis would spin faster than a disk on the rear wheel, but he calculated the surface speed to be the same, (so the heat would be the same). It heated up faster and tended to discolor, (something not seen on the wheels of a dirt bike disk). There was not as much surface area and material to dissipate the heat as well. Today, my modern dirt bike has a bigger disk yet,---and it is way too powerful for me,---until the tire slips. You do a good vid.
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Valid point IMO.
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I love the technical aspects of this mans vids. But he missed the most important part about "Being Brilliant". Why be brilliant, (or strive to be)? Because it is human to think. It is also real free enterprise, (in the hands and minds of the entire citizenry), that allows us to think and achieve to our greatest potential.
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I was thinking along your 2nd point also. It very well may not be a power curve that is easy to control. They can try to control the power with things like electronic traction control, (which I am not a fan of). But to bring braking (anti-lock brakes) into the argument, I can actually stop is less distance on slippery roads by pumping the brake petal, (and paying attention to traction), even if the car has anti-lock brakes. IMO, a smoother power delivery, and the use of a manual clutch is hard to beat. Talent, is hard to beat. :)
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@ABoringTool Yes, those are losses that the power has to overcome. But the biggest challenge for power is acceleration, especially up hill. I have my first auto (a Jeep) that has real time average gas mileage digitally displayed, and acceleration/up hills, ruins any chance I have to over 20 mpg or better. :)
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I remember Honda working with them at about that time (90's), with heat being the issue of failure. Honda at that time, was no engineering slouch.
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"and reducing emissions" That sir, is the reason why a car costs about double what it would if we were free from the EPA and other government regulations.
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Yep. A term I heard for it is "DeSaxed", but not from a reliable source.
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I didn't think of that. I guess the "recovering spring" (returning to max length), would put rotational force on the back side of the cam lobe. Has it been shown to actually cancel the compression forces of the springs?
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Ohhh, I love correcting YT vids about things I know a lot about. Let's see what cha got! Ohhh, I have a list. But I must say, you did a pretty good job overall, and I even learned something, that will be in the list. 1) I am not sure, and this is picking hairs, but I bet the 4-stroke intake valve says open a bit longer than BDC to take advantage of a bit more cylinder filling with the intake velocity. 2) Only the red environmentalist have an issue with some of the charge of a 2-stroke going out of the exhaust, and they have their own irrational motives for pushing it as a problem. I can not take their arguments as a issue in reality. They want us poor. They are communists, anti free market communists, but they love to steel our free enterprise to fund themselves. They don't deserve any recognition. 3) There are actually 5 phases, mostly overlapping, in the cycle of a 2-stroke: compression, combustion, blow down, scavenging/transfer and intake,---I think. :) 4) I think Motocross is throwing out the "2-stroke makes twice the power of a 4-stroke per displacement. The modern 450cc MX 4-stroke is making about 65hp and the old monster CR500 2-stroke made about 60hp. Now that is for MX, and the engine power delivery has to be controllable. The EPA got lucky, (forced the expensive 4-stroke on the MX industry, called a dictatorship), because the pulse of a 4-stroke does hook up better to the ground, as proven now. But even for a high rpm application like drag racing, I have a hard time believing a 450cc 2-stroke can make 130hp naturally aspirated, (of course for a 2-stroke) on gas. 5) Reed valves do still flow a bit after BDC do to intake velocity, which is why I assume the intake valve of a 4-stroke may stay open a tinge longer. 6) I have seen HP 2-stroke engines run a gas/oil mix as rich as 10:1. RC boat racers with 30cc 20,000rpm engines run that thick quite often. If the jetting is good, the combustion is hot enough and the oil burns. I think it is overkill, but they run it. A company named Quick Draw, making their own engines for TC boat racing insists on a mix that thick. But I think it is because the steel honed cylinder liner eats up the ring quick until the hone smooths out a bit. Other guys are running 10:1 with plated cylinders. Some even run Colman fuel mixed with oil still, which I really don't get at all, but they run, and lubricity is fantastic from a tear down I did for a customer. 7) Oil injection is no more modern than me mixing for a new MX bike,---and sorry, but nothing can be more reliable. Race bikes in MX still do not use oil injections, sans KTM now with transfer port fuel injection with a new oil system---that can break down. I replace a piston/ring once a year, about $150.00, for about 5 years for the plating to wear through. 5 years on a MX 4-stroke will cost a lot more. 8) 17:34 Man, that is some fast oil consumption. Still,---it ran the whole time huh. Must be jetted well. :) 9) You bring up emissions again,---and I will rationally ignore it. I will not agree with communism, ever. We need to tell them to get bent. 10) 21:37 graphic. That compression ratio/drawing is actually wrong. The 125cc is the swept volume of the piston only, not the head volume, (which you have at 12.5cc). So the proper math is (125 + 12.5)/12.5 = 11:1 I have seen professional engine tuners get that wrong, but I scratched it off as old age. 11) 2-stroke compression is also effected by the exhaust pipe effects. The returning sound wave actually bounces off the diversion cone (a point just past half it's length.), and not the earlier infuser cone, (that one is for a vacuum, to actually suck a negative pressure into the cylinder to aid scavenging, measure up to -7psi in some old writes. This happens as soon as the blow down phase actually ended, and kept sucking for a bit. The cylinder must blow down the pressure after the ex port opens to zero before the transfers open, or the pressure will force a burning charge down the transfers, (you will see black deposit on the transfer walls, and could indicate a pipe problem,--but my 88 CR250 still ran great.). 12) I am a 2-stroke guy, (for a living), and I learned about variable valve timing for some 4-stroke engines. Interesting, but I bet the cost can be blamed on the EPA force, (which communism in china does not have to deal with. The planet stops there i guess.). 13 That is the first Yamaha ex power valve design, the rotary design, (and it was a smooth transition). The guillotine style is a more modern design, and has linear movement. 14) The ex power valve is not related to the return sound wave as you suggested. The sound wave is pretty much a fixed speed, (goes a bit faster in a hot pipe), and that means it is related to piston speed. The reverse wave is also only pretty effective, (super charging effect) for a range of a few thousand rpm's, (or the fresh fuel would not leak out the exhaust.) The valve does not seal very well, if at all for added compression or down stroke sealing for power, but I would bet there is some overlapping factor there. The higher port lets exhaust gasses out faster for the higher rpm piston speed, (as with higher piston speeds, the ports are open for less time), and some people don't agree, but I think compression should be adjusted accordingly with a mod like raising the ex port, within limits of the application. To ne quite frank, I am not totally sure about the effects of a lower or higher ex port, but a lower port is used for lower rpm applications for more low end and mid range power, and a higher port leads to more top end power. But the pipe effects of the returning sound wave,---can not cover both. 15) I don't know if direct fuel injection will become the EPA forced norm. I know it has been done, but for example, KTM choose to inject it in the transfer port walls. I know it does not have pressure or heat to deal with there, and I am sure those were factors in their decision. That looks like a lot of stuff that I corrected for you and your viewers, but you covered a lot of stuff, and I think you do a pretty good vid. You are good at teaching, but we must know the details or we might as well figure it out for ourselves. The next one should be better. :) Doug in Michigan
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From what I understand, the positive displacement supercharger (shown at min 11:48), was invented for coal mining, forcing air into the deep mine shafts so the employees can breath air down there.
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TDC, Offset engine: Which is correct measurement: When the crank is perpendicular, or when the piston is actually at the top of it's stroke? Piston/rod pins are also offset on many engines and the cylinder still on center. Does that effectively do the same thing? Good vid sir.
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No tattoos or body piercings, colored hair. Good enough for me. :)
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It was much better, with more real progress,---when we did not bend to the expensive dictatorship demands of the likes of the EPA. It's none of their business. :)
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They can be re-build-able. First, if it is good plating, (Like the legendary Nikisil), it can last for several sets of pistons and rings. 2nd, they can be replated. If the cylinder sustained a lot of damage, a sleeve can be machined in place, which I think can also be plated.
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@crazyr0m He has very good knowledge. But bringing up a "environmental impact" shows he knows nothing about politics, and he does not know he caters to communism. Every wonder why china did not get EPA regulations forced on the trade agreements for the production they do?
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If the EPA (example in the states) was about "saving the planet", then in the trade agreements with communist china since 1978, EPA like regulations would have been included in the trade agreements. That alone tells me it is not about saving the planet, but to advance communism globally. Western Culture production (wealth making production), was hindered by the regulations, while communism got a free ride.
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The more we are forced to appease the EPA, the less sense it makes, (anfdthe more expensive production is).
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Rotary valve intake systems are nice for a 2-stroke., but a bit bulky when engine size is concerned, (like wider cases on a dirt bike). But they are very adjustable for duration. They can be adjusted for "open time and closing time" independently, where a piston port modification is symmetrical, and a reed valve is an obstruction. But for the exhaust, heat is the main problem. Honda worked with the rotary valves in the 90's and gave up.
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How much money?
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A 1970's Chevy small block V-8 can easily make 300 hp, and still get 25 mpg. Did not cost nearly as much either.
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Man, It is you again! I saw the vid headline and came here to critique your knowledge. But you know what you are talking about (rare on YT), and took all the fun out of my morning. :) Doug in Michigan
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@ArcticTraveller-o7s A sharp old school guy. How refreshing. :) My buddy had the 76 125 Elsinore and used it for hill climbing, (which he did well with in the 125 class). He went the other way and put a 38mm carb on it. I rode it once, (or tried to). That bike had zero power until about 10,000 rpm and maybe a 1000 rpm power range. You had to pin it to get the thing moving, or you would just stall. We lived in great days of USA MX back then, (gone now). Bike are so expensive today, if that was yesterday, we never would have rode/raced, and the record books from 1968 to about the mid eighties,---would not have anybody we know there. The best in the world, would never have ridden, as kids today can't afford their won bikes. They call it "progress" in our schools today. The progression of decline. Now a global government dictates what we make and buy, like the expensive 4-stroke that was forced on the industry by the likes of the EPA, that no kid can afford on his/her own. So sad. Oh yea,--how do you like the technical knowledge (none) of MXA today, which is now just a sales brochure? Man, we used to read MXA bike tests and know exactly what we were buying. My 2019 YZ250 2-stroke that I bought (after reading the modern MXA test), was a total shock, and needed a lot of work to make it a good bike. They said the jetting was good even. Obviously, MXA does not know how to jet a carb anymore. Richest jetting I have ever seen from a new 2-stroke. Doug in Michigan, (that has not produce a factory rider since Kelly Smith over 2 decades ago, with the activity pretty much dead in Michigan now.)
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