Everything You Don't Know About 2 Stroke Engines 🤯

[@powerwagon3731]

I liked the crankcase case compression ratio explanation never thought of that!

[@stco2426]

Agree. I had no idea.

[@RonaldDaub-v9y]

@@powerwagon3731 that's why crankcase seals are a must

[@RonaldDaub-v9y]

@@powerwagon3731 absolutely when the Piston goes down it charges the bottom to make the mixture go back up Through the transfer ports to both blow out the exhaust and charge for the next power cycle And the timing is in the placement of the ports the Piston is the valve in a piston port engine.

[@RonaldDaub-v9y]

@@powerwagon3731 that's in a piston port engine. A case read induction is a little bit different but not much rotary valve is self-explanatory usually. Then you have your twin piston twingle engines that still use ports.. but the best running ones in my opinion are the twin cylinder alternate firing like a 350 Rd Yamaha or a 500cc twin titan Suzuki

[@KlaasKamminga]

Me neither.

[@nascer2979]

Thank you so much for such a great video! I'm a two stroke freak and I waited so song for this video 😁 Could you make a video about heavy duty engines and its durability? I would be greatful 🥰

[@Eduardo_Espinoza]

The most humble face reveal without asking for likes :) liked

[@cheesebusiness]

Where?

[@rabbitfootedkitty1339]

5:22

[@karthickrazer4680]

Four Strokes Moves Your Body, Two Strokes Moves Your Soul.....

[@AlanMydland-fq2vs]

what power❤

[@Jordan-sy7my]

It only takes 1 stroke to create that soul 😂

[@rudolphguarnacci197]

I like that. If i remember i'll use it.

[@BrianMarcus-nz7cs]

May the lord bless U 🐦🐿️👍

[@suspiciousskepticism6306]

​@@Jordan-sy7myonly if you using one hand..🫡 lol

[@ATomRileyA]

Great video really explains it all so well.

[@JC-gw3yo]

I love the 2 stroke in dirt bikes, snowmobiles and jet skies.. There is nothing better in these applications

[@awesomeproducts1582]

For sure, and people still wanna argue that 4 strokes are better 😂than

[@ct1762]

Outboards are absolutely awesome in 2 stroke configuration as well.

[@paulsawczyc5019]

@@awesomeproducts1582 It's the noise and oil/fuel mixing that people don't like - plus smoke.

[@EarthSurferUSA]

@@paulsawczyc5019 Just the commie EPA son,--who duped those people. Properly jetted for the most power, and they actually make very little smoke. Only on start up. What I don't like is the EPA force, that drives up the cost of everything,---which is why you won't be able to afford much.

[@asdasdfdf-zn7lv]

@@paulsawczyc5019 those people need help because thats the best part about the two stroke

[@alimechs]

Good update keep it up the good work 👍👍

[@dwaynemcallister7231]

My Dad's old tractor was a two stroke diesel, it was called Field Marchall was made in the UK in the 1940's, it had a 9" piston.

[@steveh7823]

Smoky two strokes largely caused by user error including incorrect fuel/oil mix, incorrect timing, worn spark plug, leaking crank seals. Adding oil to fuel lowers fuel octane so two strokes run cleaner on high octane fuel 95+. Timing is extremely critical, down to fractions of a millimetre, about 1mm below TDC. Water cooled two strokes are much quieter, more efficient/powerful than air-cooled. Engine braking on a long downhill can definitely hurt a two stroke. (Just my 2c worth 🤔 as a 2-T fan)

[@prasandiluthakalansuriyapr2539]

I haven't found any video explaining this much details about 2 stroke engines... everything is there.. all the secrets behind I hv learned through this... pls keep up ur work... Thanks..

[@EarthSurferUSA]

Why do we give praise and agree with people when they really don't know exactly what they are talking about? Because we don't know the difference. I do. :) Sue your schools son. They do the same thing today.

[@AuMechanic]

Good animation, covers it mostly. A few points missed but nothing major.

[@pauloconnor7951]

Yeah not too shabby !. Where in Au are you ?

[@repairman22]

Hi. Tell me those points so I add them in other video. Thank you!

[@AuMechanic]

@@pauloconnor7951 In Melbourne, Sthn Burbs, grew up here.

[@AuMechanic]

@@repairman22 A bit too lengthy for the comment section. I do 2T vids that go down the rabbit hole on each topic so maybe look over those if you like. I sent some via your email. But as mentioned your vid covers the basics fairly well.

[@dcbacon1]

@@repairman22 How about "3rd Port" motors, like my Mac 45 go cart motor. There is a port that uncovers during the power stroke that pressurizes the incoming fuel/air before it reaches the reed valve. This allowed us to beat Corvettes 0 to 80 on a Little Indian minibike (24" wheel base).

[@EarthSurferUSA]

If the environment were a legitimate concern, then why over the last 45 years of giving our free enterprise and production to communism in china, has there never been our (western culture) EPA regulations added to the trade agreements? communism gets a free ride, while we, who created free enterprise in the first place, are punished.

[@AlanMydland-fq2vs]

point well made, u should of been president😂😂❤

[@Pentium4-ExtremeEdition]

😢

[@gpromburgh]

Ignorance+corruption is bliss is what it boils down to 🙉🙈🙊

[@vjiglesias5815]

Cause the chinas make awesome duck sauce

[@SteveCrider-c2r]

KKKalifornia was the reason for the 2-strokes demise.

[@yiorgos272]

Fun fact: There has been (at least one I know of) experimental engine that used electronically/hydraulically controlled poppet valves and would work as either 2-stroke or 4-stroke depending on the load. 2-stroke under high load for power, 4-stroke under low load for fuel efficiency.

[@EarthSurferUSA]

I bet neither mode works as well as they do in separate engines.

[@agungh1670]

Koenigseg

[@Lynet364]

No?😂​@@agungh1670

[@bryanspanjer3213]

I would have liked more explanation of the power valve. I think you briefly described it before you went over the pros and cons at the end. That is the part that broke on my Suzuki 125 back in the 90s

[@RonaldDaub-v9y]

@@bryanspanjer3213 in a two-cycle the height of the bottom of the exhaust Port is adjustable with the power valve In the older engines without the power valve you chose it.. was was not adjustable except with a grinder and it stayed that way.

[@ovalwingnut]

GR8T animation! See, this is what the Interwebs are acutally for You R the "Two Stroke Engine Whisperer"

[@SLAYJUCE]

Top 5 two stroke engines 1. All 2. Of 3. Them 4. Are 5. Sick

[@Akeirbuah]

2 stroke go braaaap

[@kevinm.n.5158]

Dang I hope they get better

[@cleonwallace2267]

thanks bro this is perfect keep it up and keep us updated

[@repairman22]

Thank you!

[@CaseyW491]

Hey, love your videos! I teach equipment operators for a trade school. Do you mind if I share some with my students and credit you? Some exposure.

[@repairman22]

Sure. No problem.

[@johnbryan9200]

That has to be the best explanation on a two stroke engine that I have seen!!!

[@remreiniger]

Fr

[@EarthSurferUSA]

I build 2-stroke engines for a living, racing applications and recreation. If you have "seen" a lot of other explanation,---they were all probably just a bit worse than this one. I give this a B- for technical information, and a F for the EPA propaganda.

[@benjamincresswell3713]

Early on I put together a Go-Kart with a 2-1/2hp Cast Iron Briggs and Stratton engine that drove 1 rear wheel. Next I received a worn out Jacobson 1.8hp 2 cycle Aluminum lawnmower engine from a friend. We put it on my Go-Kart and it was so cool. It didn't go faster or quicker, but my Go-Kart seemed lighter and it had a very silencing muffler that made it just purr, like a Honda 50. Eventually as I upgraded my Go-Kart I went back to a 4 stroke Aluminum Briggs rated at 7hp. It was about the same weight as the 2-1/2hp Cast Iron engine but had tremendous get away and topped out at 50mph at WOT no governor. One day I came across a McCulloch 2 cycle chainsaw engine. It was very powerful rated between 7 and 13 hp. My Go-Kart had evolved into a low slung racer and now it went 65mph. Then I got another McCulloch nearly the same size and mounted it on the other rear wheel. It took some work to get it to run backward, but eventually it did. If you can imagine two 7 - 13hp engines on a small Go-Kart, it meant 90mph +, but I had no way to clock it. I was Sixteen then and just learning to drive a car, and so were all of my friends. Finding someone to clock my Go-Kart at over 80mph just wasn't available to me. Besides, I was 16, I could drive the car! Good Bye Go-Kart. I gave my Go-Kart to a neighbor a little younger than me. Hello Cruising Woodward Avenue. Enter 1969 Plymouth GTX. I still have the GTX. ben/ michigan

[@EarthSurferUSA]

For the tuned pipe, it is not the change in pressure through the pipe that causes the "reverse wave", but a sonic wave, (sound), that bounces off the reverse cones. The expanding gasses in the pipe create the vacuum that help draw out free gas from the transfers, into the cylinder and some out the exhaust port. It is the sonic wave that pushes that fresh charge back in the cylinder for a super charging effect, which is why tuned pipe make much more peak power (but not in the total range of usable rpm's, as it relies on piston speed match to a tuned pipe.). Maybe the creators of this bot channel should have consulted with me, to be more accurate, (less false information).

[@EarthSurferUSA]

Now to get more peak power, rpm's usually have to ride, (part of the equation), and it is usually true for racing or performance engines to seek more peak power, especially for racing like road racing. But, the fact is, a pipe can also be made to enhance lower rpm power, like many pipes sold for off road use in dirt bikes. The type of power can be changed for the application greatly, with pipe and porting. I can tune a pipe to peak at 8000 rpm just as easily as peak at 16,000 rpm, by changing its tuned length.

[@EarthSurferUSA]

Now to get more peak power, rpm's usually have to "rise". sorry

[@RonaldDaub-v9y]

@@EarthSurferUSA some of our motorcycles and RPM expansion Chambers and other two strokes could be tuned with a torque pipe. Of course other things in the engine would have to match the expansion chamber's job or duty. I remember having the Peakyist 90 CC Yamaha MX ever . It needed a toggle switch instead of a throttle. The 90 Yamaha had a RPM expansion chamber as we called it.. because that engine was not going to make that much torque unless it would be detained to a trials machine with heavier flywheel in different porting

[@EarthSurferUSA]

@@RonaldDaub-v9y " It needed a toggle switch instead of a throttle." :) Good post. But the best way to build a engine is make the porting for the application, then make the pipe to match the porting. But IMO, if they are just judged on their own (porting or pipe), pipe effects can change the power output more than just porting.

[@EarthSurferUSA]

KTM (appeasing expensive EPA force), found out in their testing that direct injection into the head, had to fight the rising compression, and became complicated and even more expensive to make, (prices are very high today because of the EPA, and market share is dwindling in the off road motorcycle industry). So they are injecting the fuel in the transfer ports or the intake with no oil, and still may have problems with the oil injection systems used for fuel injection for the 2-stroke engine. Expensive KTM dirt bike engines today, are not a model for top reliability. But they are the most expensive. Thank the EPA.

[@IbocC64]

Not going to mention anything about Snowmobiles using engines that run backwards to shift in to reverse? This has been how Ski-Doo does reverse with a system called RER that has been available since 1998 on some models and on all models since around 2002 or so. You press and hold a button and the engine stops for just a quarter second or so, then kicks backwards. The computer then emits an audible BEEP to let you know you are in reverse. Like a semi backing up. Somehow this does not require an electric start. Not clear on how that works. But since it is a pull start, it can only start in one direction normally and you use the RER to stop the rotation and spin it backwards.

[@TheBMWDrifter-sb2cy]

Your videos are the type of videos I didnt know I needed, this stuff is really cool. Please continue!!!!

[@EarthSurferUSA]

I do know, what this vid and you don't. When you don't know much, any information can be seen as correct information. That is why we graduate form our schools today,----------------------stupid.

[@alanstrong55]

FYI: Must mix the gas and oil. 2 stroke engine oil mandatory. The motor is louder. Just the right motor for a dirt bike. Climb that hill. Have fun on an open field. Yamaha said it is all right. Enduro!

[@anandajanka]

This animation is good for the teaching to automobile student. Thank you very much

[@EarthSurferUSA]

I have seen one two stroke engine start backwards. It was in the 70's on a Husky 250cc dirt bike. It was funny. I saw my buddy start up the engine, put it in gear, took off a bit and the roost hit the front tire. The culprit? The flywheel key was sheered and the timing changed enough to backfire (on the kick), and start backwards. It sounded like it was running good too. :)

[@MichaelLyons-h4i]

It's happened to me on two different dirt bikes

[@MichaelLyons-h4i]

Bring back 500 CC 2-stroke motocross bikes 💪💨

[@billmalec]

Glad you say 2 stroke and not 2 cycle.

[@RonaldDaub-v9y]

Same thing 😂

[@smitajky]

The lightburn zeta used the changed timing and starting its engine in reverse to avoid having a separate reverse gear. (meaning it had 4 reverse gears). What you have also overlooked is that the moment that the points close in forwards is the moment that they open in reverse. It is possible that with a short dwell the timing of the spark is quite normal in both directions. This happened to me with my Kawasaki F2. It had an electric start. I pressed the button and the engine started. It sounded a little funny. But I gave it a few revs and let out the clutch. Straight backwards into the wall of the garage. The first spin had filled the engine with mixture but then it fired and kicked back. Starting the engine in reverse. Funny in a way.

[@rudydalessandro1094]

I own a 300 2T enduro bike, there's nothing like the power delivery of a 2 T engine.

[@Eduardo_Espinoza]

There are cleaner lawn care 2t engines that leak clean air in front of the transfer ports so it's clean air 1st then a/f mixture, since the 90's-Present (RedMax: Strato-Charged). :)

[@pauloconnor7951]

Really ?. Who does that please ?

[@Bill-sp8kb]

​@@pauloconnor7951That's irrelevant. The only things that matter, are power, reliability, and light weight.

[@ct1762]

@@Bill-sp8kb i agree with that but for boats, having a DFI 2 stroke that gets 35% better fuel economy at cruise is huge! some are even better than that like an OptiMax

[@KlaasKamminga]

Very informative, thanks! The rotating disc valves can also be simple flat steel halfmoon discs pinned to the cranckshaft like a Trabant engine uses, almost no weight/complication penalty. In this case they are used ( I assume ) to let the engine breathe better at fairly low revs to let it pull from there. Even the completely standard piston controlled engines can be tuned for working at low revs, like a DKW engine from the 1930's. At the expense of top end power, but better drivable on the street, especially back then.

[@RonaldDaub-v9y]

You can also have a reed valve on a piston Port engine.

[@stco2426]

Excellent details and very comprehensive. Thanks!

[@JS-oy6nn]

Most of my 2 stroke knowledge is in chainsaws. Intended use for the individual saw dictates the shape and timing numbers of the ports. I have all my saws professionally ported for the simple reason the man who does all my saws is an absolute artist with a lathe and grinder. .003 can mean the difference between an incredible running saw and spending $275 for a new topend kit, plus the tools are quite expensive.

[@AndyGenova-jr9ol]

I'm a chainsaw mech went to college that guy is having u a different sound to make appear supreme want Dino results most are done on hopes n dreams sorry true facts great hope u bought in more ware thanything

[@EarthSurferUSA]

Funny a bit. 9:58, on the dirt bike with a go-pro on his helmet: "Do I take this line down the hill, or this line?" He choose the easy one. :)

[@EarthSurferUSA]

1:50 Oil burning is more blue in color. White smoke (steam) is probably a water cooing leak into the cylinder. Good crisp jetting greatly reduces that smoke you see in that example.

[@dipstiksubaru3246]

That's not a liquid cooled engine so yes that is 2 stroke smoke.

[@pauls5745]

can be bluish, depending on mix ratio...

[@RonaldDaub-v9y]

​@@pauls5745two strokes are supposed to smoke a little if they're not they're not getting lubricated

[@pauls5745]

@@RonaldDaub-v9y I don;t want to see what smoke comes out if it's not getting lube hahaha. but yes. A well-tuned a 2 stroke will still smoke.

[@wonkylommiter6364]

Thank you. I didn't understand how important the exhaust/expansion chamber was on a stroke engine but you explain it well.

[@paulsawczyc5019]

Yeah - it's almost kinda like a pump.

[@EarthSurferUSA]

Nope, the bot did not explain the pipe well. It may be the most naive explanation I ever heard. I have made a living modifying 2-stroke engines for the last 2 decades. I see a brain dead bot here reading from a ill educated HS research paper. :)

[@I.M.SofaKingdom]

What did the bot miss?

[@MichaelLyons-h4i]

​@@EarthSurferUSAwell I'll be damned you're right again EarthSurfer

[@tadonplane8265]

The port leading from the carburetor to the crankcase is the intake port. The port leading from the crankcase to the cylinder is called the transfer port. The transfer port and the exhaust ports are the ones open at the same time, the exhaust and the intake ports never are. A three port engine is also called a loop charged engine. Nearly all two stroke outboard motors are reed valve engines. In my personal experience I’ve only ever seen two rotary valve two stroke engines. One was a horizontally apposed twin cylinder McCullough US Air Force surplus drone engine. The other was a 90cc Suzuki street bike. The owner told me it had no carburetor because is wasn’t on the cylinder. We found it hiding under the side cover. When we removed it we could see the rotor through the intake port, and could expose the rotor port by rotating the crank.

[@yiorgos272]

Rotax 2 stroke engines used in microlights (jet-skis too?) have rotary intake valves. Also, model airplane engines typically have hollow crankshafts that incorporate rotary valves

[@user-pg4mm7ll2x]

Traditional 2 stroke Vespa motor scooter engines use a rotary valve intake.

[@EarthSurferUSA]

"The transfer port and the exhaust ports are the ones open at the same time." Nope. The exhaust opens much earlier then the transfers. The cylinder pressure has to "blow down" to about zero pressure, so the transfers can flow into the cylinder. The measured number of degrees of crank rotation between the exhaust opening up, and the transfers opening up, is called "The blow down phase". It would not run if they opened at the same time. "Loop Scavenging" is the correct term. I would like to build a rotary valve engine from scratch. I think I can get the most power form them.

[@tadonplane8265]

@@EarthSurferUSA I didn’t mean to imply that they both open at the same time, you are correct, the top of the exhaust port is higher in the cylinder than the top of the transfer port so that the high pressure in the cylinder can blow out before the transfer port opens. They are both fully open though at bottom dead center. The intake port is never open when either the exhaust or the transfer ports are open.

[@MichaelLyons-h4i]

​@@tadonplane8265the EarthSurfer is always right 🤷

[@ethan_martin]

is there no way you can remove the air intake port and add an oil pump to a direct injection 2 stroke?

[@michaelmcgann6296]

Great video . Very well explained. Love the 2 stroke . Simple design and they do so many things. I think there was a Detroit diesel 2 stroke too. Lovely sound out of it. Thanks for the great video .

[@goodoleme747]

I was hoping to learn more about power valves. Good video

[@walkawayjoe]

How is crankcase lubrication with direct injection?

[@RonaldDaub-v9y]

There are also two-stroke trials machines that produce nothing but torque. It's sad to say a two-stroke is just for RPM it can but it's not just for RPM

[@jeremyrichards8327]

No mention of Schnuerle porting which is more effective than loop scavenging?

[@EarthSurferUSA]

They are the same thing. Schnuerle (sp?), developed "loop scavenging". You are right though, the programmed bot missed that,--and the fact that a sound wave in the pipe, that the bot confused with only pressure.

[@EarthSurferUSA]

8:40 The bot vid is comparing a corrected compression ration (7:1, the area only above the exhaust port in the stroke), to a 4-stroke method (12:1) using the full stroke of the bore. People do measure 2-stroke compression with the 4-stroke method, (which is not a good practice IMO), but the corrected method is just for 2-strokes. You will not find a 2-stroke with 12:1 compression, (measured by the corrected method), that will run on gas with out failure,---quickly.

[@veoverse4286]

Why does the hot exhaust not ignite the air/fuel mixture, when the exhaust and transver port ist open at the same time?

[@jackcarterdrelias]

There is also a french Motorcycle, the "99z", having a second piston : a simple piston, without sparkplug, supposed to act as a "balance piston" in order to increase balance to the crankshaft. But this was rather designed to suck and push more gasoline into the combustion chamber for more power. You should google it, this was quite an innovation at its time. I wonder why this didn't became a standard.

[@davidstuck2866]

You forgot 2 stroke outboard engines for boats (up to and including V-8 engines) and inboard Jet Ski watercraft's. as well as snowmobile and ultra-light aircraft engines. you also did not mention just how many 2 stroke die hard fans there are around the globe. NOTHING can compare to the lightweight horsepower that can be achieved with a highly tuned 2 stroke. and the really odd thing about those highly tuned 2 strokes, is they can also be quite fuel efficient at the same time. Also, those "heavy" rotary valves and reed valve parts that you are describing, weigh in at less than 8 ounces typically if properly designed. the "loop charged" deflector pistons were ridiculous though. they were a very poor design. and limited R.P.M. SIGNIFICANTLY.

[@ct1762]

not loop charged you mean cross flow. yes they had heavy pistons and less potential as in a looper outboard, but they idled like a sewing machine and most where very quite.

[@EarthSurferUSA]

@@ct1762 "Loop scavenging" replaced "cross scavenging",---a long time ago. 70 years maybe?

[@EarthSurferUSA]

Finally, a guy who knows what he is talking about. Kudos. Doug @ ESP (Earth Surfer Performance).

[@truethought369]

Meny years ago, I had a CZ-125, for a short while. I stopped at a junction, & when I went to pull out onto the main road, the dam thing tried to reverse back onto the road I was leaving??? It had to go, #@?! The point being, it will run backwards,! Thank for the diagrams. P/S, top tip if you have an old 2-stroke, like the BSA Bantom? When rebuilding, always renew the crankshaft oil seals, even if they look OK. Your primary compression depends on them.

[@AndyGenova-jr9ol]

No shit

[@tomwolf4609]

Very well done..Good video.!

[@supertenchung2413]

why the spark can constantly fire (always -on ), no need for some kind of ignition mechanism?

[@pancudowny]

What about turbo-charging a 2-stroke engine? Is it possible? If so, what dynamics must come into play for it to be effective?

[@tomahoks]

Sure. It can also be supercharged.

[@alleeriksson3530]

Check out modern snowmobiles, ex. Rotax 850 turbo r

[@AndyGenova-jr9ol]

Weight to power would totally melt down not a true turbo

[@ericwilson2585]

Don't forget about if/when the float needle sticks open and floods the crankcase with gas and then you can't get it to start for days because of it. Or when the crankshaft seals wear out and you can't get it to start for days because of it. Or what about when the crankshaft seals are worn-out and your trying to slow down at an intersection and the engine starts accelerating uncontrollably because of it?

[@ct1762]

what are you talking about? im an outboard mechanic and have only seen 2 crank seal leaks in motors from the late 1970's on through the early 2000's have a crank seal leak. o rings and oil seals. extremely effective!

[@EarthSurferUSA]

@@ct1762 He is talking about the normal maintenance that he is too lazy to do. Factories usually don't sell new engines in those worn out conditions. :) Pretty sure this guy hates shoe laces. Too complex, and he does not have time.

[@MichaelLyons-h4i]

I used to have a 1972 Ski-Doo one lunger snowmobile that would flood out something terrible into the crankcase. I used to keep a propane torch with me you take out the spark plug pull it over slowly and squint at the same time. Boom!

[@kcinbnavi]

Is there a more complete burn of fuel and air mixture using direct injection, eliminating unburned air polution?

[@EarthSurferUSA]

7:00 Another ill educated bot error. Pressure does not cause the reverse wave in a tuned pipe. Sound does.

[@EarthSurferUSA]

But, the back pressure will help hold in the fresh gasses from leaving the ex. port at lower rpm's, before the sound wave is in effect. We use the calculations of "sound speed" to created a proper length and geometry tuned pipe. If you build too much pressure, (a small diameter exhaust end bleed, the end of the exhaust), then the engine will get hotter at higher rpm, like the close cats on your car overheating your engine in an effort to burn every hydrocarbon. Nope, the EPA does not care how long your gas engine lasts, unless it is a shortened live span. I don't see Toyota ads today, like we did 40 years ago, bragging about 300,000 miles.

[@lucasmunnery5548]

⁠@@EarthSurferUSAA pressure wave and a sound wave are the same thing, a sound wave just oscillates so that it has a frequency as opposed to the singular front of a pressure wave.

[@bluesky6985]

Smokey Yunick said 2 stroke is the way to go

[@jamescampbell4334]

Too bad the EPA refused to listen to someone with the name 'Smokey'. 🤔

[@MichaelLyons-h4i]

​@@jamescampbell4334f*** the EPA

[@johnburton6984]

A truly wonderfully detailed and commented presentation.. Thanks

[@EarthSurferUSA]

How do you know?

[@EarthSurferUSA]

7:40 That is also not true. My dyno reads with different types of exhaust, or none at all, (as I calibrated my dyno), with these 3 different runs: 1 Tuned pipe makes the most power. 2) No exhaust at all made the 2nd most. 3) A stock exhaust can, (found on all lawn equipment for example), made the least amount of power. (Pipe almost doubles that power). On the engines I work on, the stock can makes about 18% less power than no exhaust at all.

[@Alexie3333]

Are there two stroke engines that runs without crankcase compression? I was thinking to design a 2 and 4 stroke engine in one (2 cyliders or 4). 4 stroke to get engine to idle and to speed. And two stroke to take at high rpm the speed. I have read that at tuned exhaust scavaging take more place and crankcase volume (and compression) doesn't really matter. But here it is mesioned that higher crankcase ratio is for high speed (where more scavaging is). Of course when hitting high rpm, the 4 stroke cylinder need to fulley open exhaust so it rev freely. I never saw this before

[@1SixpenceFan]

I wish I had a dollar for every time I've felt a 2-stroke power band, it would be in the six digits without a doubt.

[@qdsfeqr]

Very well explained man! Helping to realy understand this type of engine!🎉

[@EarthSurferUSA]

How do you know? You don't.

[@stefanm67]

This is an excellent video. Thanks for taking the time to make it. I found it very informative and I'm looking forward to watching more of your stuff. 👍

[@EarthSurferUSA]

How do you know? I do. :)

[@derf9465]

Never seen a crankshaft like that ....what till you start playing with squish, deck heights, port design, expansion chamber dia. Its fun and frustrating

[@EpemaKlapkin]

Производится ли серийно двухтактные двигатели с впускным клапаном в ГБЦ?

[@kapokimuramasa]

排気ポートの方が先に開くということは閉まるのが後になるってことなんだけど、チャンバーからの衝撃波が帰ってくることで圧縮行程時にはポートが閉まった状態になる。知らんけど。

[@TaBeXD]

Great video. It would be cool to see images of the actual parts like reed valves etc in the video.

[@AndyGenova-jr9ol]

Buy one n take it appart learn by doing

[@holydoggo7925]

Why not constantly pressurize the intake? So when both intake and exhaust are open, the pressure in the intake will push all the used air out and feed fresh air in at the same time, minimizing the oil coming in, since the air doesn't need to enter the crank case. The crank case can be also modeled like on the 4 stroke engines for lubrication. I think the downside is, it will be required to use injectors. Is it a dumb idea?

[@EarthSurferUSA]

You are talking about supercharging the intake. But on the 2-stroke, when the transfer ports are open, filling the cylinder, so is the exhaust port. So it all blows out the exhaust. I am sure the flowing action would clear out the burnt exhaust gasses better in the head and cylinder area, and maybe find a bit more power because of that purity of fresh fuel/air. But you will be blowing a huge amount of fresh gas/air out of the exhaust port at the same time. Until communism in china has to deal with an EPA,---I have to consider their arguments against gas engines, coal electric generation, etc., a load of crap.

[@pauls5745]

sure. can be done but it's very hard to force-induct a 2 stroke. so much boost is lost to the exhaust port, but proper port timing can minimize this.

[@chris2pher44]

Had an atv with 2 stroke. I wanna get another atv but as we all know they can’t produce them here anymore. Could change the top and piston under hour. Just have to carry some spare reeds with because they’d crack once awhile. Kids will never get to experience “powerband” guess now it’ll have to be turbos Correct me if I’m wrong but thought Yamaha or Honda made a 2stroke last couple years that was cleaner than the typical 4 stroke?

[@EdgeMaster9000]

Love the smoke and smell tho

[@MichaelLyons-h4i]

Especially if you're burning castor oil

[@fridaycaliforniaa236]

Tes vidéos sont excellentes =)

[@StreakyP]

I had a 2 stroke BSA Bantam D1 that would come to a grinding halt, whip the plug out, fingernail through the plug gap to clear the carbon whisker killing the ignition, pop plug back in & be on your way again... that wasn't a break-down that was just a normal journey

[@AndyGenova-jr9ol]

That was a bad port design trust a stranger

[@niconine268]

Great video Thankyou. Subbed up

[@gigabytegb]

Fantastic! I will come back to make questions, and more questions to develop simplified and cheaper electronic ignition (or piezo atomizer😅) and injection, with cheaper sensors and microcontrers like ESP-32, photodiodes for monitoring temperatures like EGT, and solve my problems with stability (and share with you) here in Brazil with this admirable trash tools!

[@hiddedijkstra5916]

Why does a 2 stroke engine run 12000 rpm? Wouldnt it have te runs half of the 4 stroke engine to deliver (almost) the same amount of power?

[@vailpaxman8472]

They run at higher rpm to make more power than 4 strokes with a much smaller engine

[@AnoNymous-xx5kb]

shorter stroke

[@CHANNEL-wp3lc]

Очень хорошо сказал информацию. Спасибо👍😊

[@jimjg9923]

What about direct injection 2 strokes?

[@areaofspaceflight]

0:04 why no no one is talking about 4 stroke engine /why 4 stroke engine Don't have that😭

[@evoluce77]

Interesting video how a 2-stroke engine works in 3D. But I think calculating the compression ratio of the crankcase at 8:32 is wrong. If the crankcase compression ratio is 1.5:1, a 50 CC engine must have a 75 CC crankcase.

[@repairman22]

When I first read it I thought the same as you. Then I understood the formula that I put on the screen. 150/100= 1.5 so, if i have 1atm, then i will have 1.5atm.

[@thanhnamtruong7968]

thank u so much

[@backys]

Perfect video

[@kevinavillain4616]

Of course the supercharged 2-stroke engine is a whole different ball of wax

[@waynewillmore]

What about loop scavenge two stroke engines?

[@EarthSurferUSA]

In my estimation from years of study, I am sure the creators of this vid know what loop scavenging is. But if they come from the perspective of the EPA, (which communist, anti free enterprise china has no EPA regulation in the trade agreements), it is to show a dirty running engine as much as possible, and no production 2-stroke engine ever had that port configuration in reality. They all like to show a lot of smoke from the exhaust of un-burnt oil/gas, and all 2-stroke engines with a carb are shipped rich to be on the safe side for air quality around the world. But that smoke can be greatly eliminated, burning cleaner, improving performance and gas mileage, with good jetting (which we have to do ourselves). With those facts left out, makes this vid a piece of propaganda IMO. Doug in Michigan.

[@cliffordgrobler]

If the blower pump on diesel was not so expensive, it will work 100% on petrol feul injection

[@vijayam1]

Brilliant.

[@jasontran6434]

There a four-stroke engine that have greater air flow capacity than current 2-stroke engine from Dynamic Alpha Automotive Technology.

[@EarthSurferUSA]

Well, you can add a supercharger to a 4-stroke, not a 2-stroke, and make any 4-stroke engine with increased flow capacity.

[@jasontran6434]

@@EarthSurferUSA Yes. You can add supercharger to increase air volume but it came as a cost to thermal efficiency.

[@mattdaddy_888]

I dont understand why the otto cycle 4 stroke is the standard in almost all vehicles instead of the 2 stroke design used by detroit? 2 strokes are more efficient since you eliminate the friction coefficient of the intake and exhaust strokes that don't produce any power and two strokes produce more torque since they have more powerstrokes per crankshaft rotation. Likewise I don't get why we don't use 2 stroke opposed piston emgines like the one achates power made but they have been around long before then in WWI WWII tanks. They have a higher thermal efficiency of 55 percent or more.

[@EarthSurferUSA]

Excluding the force of the EPA, probably the longevity of the engine. A tame 4-stroke ( not a racing engine), will go a lot longer than a 2-stroke with out a top end rebuild, but costs much more to rebuild it.

[@ludgerheitkemper6501]

ALL of this i know 45 Y years ago! Nottingham new!

[@allanweseman5433]

I am chomping at the bit awaiting to hear WHEN Yamaha's new revision of the RD350 YPVS will arrive in 2025, when I will gladly plop down cash and be the first person out the door with one

[@AndyGenova-jr9ol]

Buy the original n pray u don't die peace out

[@andrewallen9993]

My Jawa 350TS has 3 rings as a 10:1 compression ratio.

[@EarthSurferUSA]

The vid is wrong with compression ratios. it compares the 2-stroke method (about 8:1), to a full stroke 4-stroke engine (12:1). 10:1 with the 2-stroke method (only the area above the ex. port is calculated), and you probably could not run gasoline.

[@andrewallen9993]

@@EarthSurferUSA My Jawa has a 10:1 compression ratio. I have a compression tester and that is correct and have to run it on 98 octane gasoline. As you say only the area above the exhaust port when it is sealed by the f irst piston ring is calculated as swept volume for compression ratio calculations.

[@AndyGenova-jr9ol]

I call my wife a jaw wow

[@andrewallen9993]

@@AndyGenova-jr9ol How many rings does she have😁

[@EarthSurferUSA]

For a "smokey" 2-stroke engine (carbed). The jetting is too rich. A well jetted 2-stroke engine does not smoke much at all, runs cleaner, and makes more power. Factories have to sell them jetted rich to not seize in different air quality around the world. But any 2-stroke stock, with a carb,---will benefit from leaner jetting.

[@graemesutton2067]

Two are strokes are the best thinnest best engines

[@motorizedbicyclenation53cu90]

Forgot piston ramping case stuffing reed stuffers port shapes crank balance floating the shaft ports inside shape degrees of duration hell a fuck ton of info

[@EarthSurferUSA]

Then I would not buy a modified engine from the bot. :)

[@AndyGenova-jr9ol]

Money complications

[@matthewfredrickmfkrz1934]

Effects of port timing

[@EarthSurferUSA]

No bot vid in the world----knows that. :)

[@hiddewind1999]

What about pistons with one piston ring arent they faster

[@liloldsnoopy4279]

Must have been faster, with less friction. Older road racing bikes had 1 ring, eg Yamaha TZ 125, 250, 350, 750cc

[@EarthSurferUSA]

@@liloldsnoopy4279 Less friction, but more blow by. Racing engines still use both.

[@AndyGenova-jr9ol]

Think longevity

[@200pluskphgang]

4 strokes = stronger power strokes 2 strokes = more power strokes.

[@EarthSurferUSA]

Is the bot sure that t-stroke ports are just "simple holes"? Because decades of research and testing to gain the most power has proven to be quite complicated. Probably much more complicated than a valve. So, I already see "simple holes" in this vid.

[@RIPPERTON]

Direct injection doesnt work because the bottom end runs too hot without fuel cooling. KTM have already proven that.

[@ct1762]

many many outboards used DFI/Ficht/HPDI/TLDI direct injection with no problems in crankcase heat! most used a vapor tank that recirculated warm fuel by cooling it down and putting it through the crankcase. oil had a seperate pump directly to cylinder walls and crankcase, which is what really helped combined with raw water cooling

[@EarthSurferUSA]

Nope, (to the best of my knowledge). KTM is using "transfer port injection", (because of EPA force). What they dropped is the direct injection into the cylinder during the compression stroke, (like this vid shows), because it requires much more pressure, probably making metering and reliability not as sound. The bottom end temps will be the same. But, there is the cooling factor you mention, so maybe I am wrong, and the bottom end just gets warmer with only oil injection on the bearings.

[@danielklopp7007]

This video has many technical errors. "Repairman22" - you might want to research the following technical details: 1. Loop scavenge two-stroke vs. externally scavenged two-stroke (hint: what you described in this video is a loop-scavenged two-stroke, with only a brief image of an externally scavenged two-stroke at the end of the video, but no description of the differences) 2. Rolling element bearings vs. fluid film bearings (hint: typical modern four-stroke engines use fluid film bearings - making the statement @5:30 nonsensical) 3. Piston port vs. reed valve vs. rotary valve induction (hint: performance figures from racing engines show no significant performance advantage for any of these, making your statement @3:00 inaccurate) 4. Rolling element bearing lubrication requirements (hint: rolling element bearings require very little lubrication - making your statement @9:50 nonsensical) 5. Incomplete description of the reason for the shape of high-performance two-stroke exhaust pipes 6. No mention of lack engine braking (aka pumping losses, aka "compression braking") 7. No mention of transfer-port injection (or crankcase injection) when discussing direct fuel injection

[@EarthSurferUSA]

As a 2-stroke engine builder myself, I would have to disagree with #3 a bit. I would say the rotary valve intake offers the best performance, then reeds, then piston port. The reason is the difference way they fill the crank cases. Reeds offer a wider power curve, (and usually more power, as piston ports rarely have a 5th transfer), over a piston port, and it flows based on different pressures and not piston location, and can have an open duration of the intake to a full 360 degrees, allowing fuel to flow when ever pressure differences let it happen. But, the reed valve is an obstruction. Rotary valve, similar to the piston port as the flow is controlled by mechanical means instead of different pressures, has the ability to tune the intake duration at closing, and opening, where the piston port is symmetrical, but is more expensive to build. Obviously, the MX factories went with reeds starting in the 70's, because they are out performing the piston ports. But I think the rotary valve has the best potential because of that intake control, and no obstruction like a reed valve. I will listen to this vid, (which is probably a bot vid, just repeating what it learned, correct or incorrect), and I bet I could find other discrepancies also. :)

[@EarthSurferUSA]

But the reed valve is of little use, if there are no reed transfer ports to increase time area of the transfers, so we can increase the time area of the exhaust port to match. I have only seen one piston port MX bike engine (an old Montessa), that was able to use a 5th transfer. It was the only time I saw that unusual casting configuration, but there may be more.

[@danielklopp7007]

@@EarthSurferUSA - finally, a KZbin commenter that knows of what they write! I completely agree that rotary valve 2-strokes have the highest potential power output (I was simplifying my comment for the majority of the KZbin audience). The title of my senior undergraduate thesis was, "Expansion chamber exhaust in loop-scavenged two-stoke engines". I did a lot of research and theoretical work, backed up by cutting, rolling, welding and testing several different exhaust systems (I even built a dynamometer from scratch for testing). My test "mule" was an old TZ-250 Yamaha. I ended up with a set of "top speed" pipes which sacrificed torque spread for top speed, and a set of "acceleration" pipes for tighter tracks with no significant straits. Those were the days (I still love the smell of burning castor-bean oil)!!