The "Squariel" remains my favourite old British bike. It's not surprising that all the other square 4s on this list are two-strokes. If you want to build a two-stroke with precisely timed input, you need to put a rotary valve on the crankshaft for each cylinder. If you want to put rotary valves on a four-cylinder engine the square four is the only possible configuration. My most memorable ride was when I borrowed a friend's 500 Gamma to race, ehm I mean "ride", down some backroads with which I was very familiar. Being a two-stroke 500 making 95bhp with a tachometer that only began reading at 3000 rpm, you might expect it to be a hard-edged, peaky machine. It wasn't: it was easy to ride fast and was remarkably comfortable.
"If you want to put rotary valves on a four-cylinder engine the square four is the only possible configuration" How do you figure? Two rotary valves would work just fine on an inline 4.
@@crookedaxle is rather limited imagination, isnt it? can be a drum/disc between each pair of cylinders, can be a separate rotary valve driven off a shaft, could even be form of poppet valve into the crank driven by a cam. with a bit of thinking, one could use the crankdisc itself as the valve... thinking of poppets, be interesting to see a reed valve replaced by a self actuating one. i keep thinking of bernoullis on reed valves... harder you blow through them, the harder they tend to "suck" together... easily proven by trying to blow between two sheets of paper. whereas the shape of a poppet valve should tend to force open as air flows faster through it... basic action/reaction type affair... but maybe i overthink things, lol. and then i got other ideas im working on and have to leave other ideas behind for later, if i ever backtrack...
The issue with self actuated poppet valves on 2 stroke crankcases is the inertia of the valve. With only at most 1 atmosphere of pressure to open it, the valve spring has to be pretty light, so it can't close the valve fast enough at high RPM. Reed valves actually have the same problem but being made of very thin sheet are light enough to work ok at rpms in the fun range.
@@nerd1000ify use the crank disc to force it shut ;) and now weve gone full circle and may as well drive it with a cam. though not having to deal with combustion pressures or temperatures, that valve and mechanism can be far lighter than the regular valve train. iunno. cant say ive ever seen a twosmoker with a poppet valve on the case...
@@paradiselost9946 Some very old "oil engines" and so forth had them, you can find videos on UA-cam. We're talking stationary motors which run at a few hundred RPM, so for them the inertia isn't such a problem! The challenge with any idea for an incremental improvement on a 2-stroke is that they're usually designed to take advantage of the 2-stroke's greatest strength: being very cheap to build. So manufacturers probably won't be willing to do anything that adds too many extra parts. Of course if you want to go crazy and just make the ultimate 2-stroke for its own sake you could do things like run a roots blower instead of using the crankcase, use poppet valves for the exhaust so you get uniflow scavenging, etc.
Square 4 is an excellent package . It makes a 4 cylinder engine with perfect balance , normally the bailiwick of the inline 6 . The " Squariel " was considered an Excellent machine , but it was prone to REAR cylinder overheating .
Awwwwwwe yeah! Not super often you find something I have absolutely zero prior knowledge of. This is incredible. This is not to say you dont teach me all sorts of things, Im just a big ole nerd and spent way too much time on the internet. I usually know a little something and learn a lot, trust me. This however is absolutely and entirely unknown to me until just now! Thanks!
Morbidelli manufactured woodworking machinery rather than "ran a woodworking shop". They expanded into metalworking machines and CNC . They are now part of SCM Group
While living in England in the 70's and rebuilding a T120 Bonneville, I came across a shop called Healy Engineering that let me use their sandblaster. Their main business was re-engineering Ariel Square 4's. They would enlarge the oiling to the rear cylinders to increase lubrication and cooling among other things, and I would be surrounded by 4+ Ariels every time I visited.
My uncle rode an Aerial Square with a Double Adult sidecar. He used to ride the outfit from Birmingham UK to Limerick Ireland, as far as I remember this was before The Severn Bridge was built so he had a very long drive.
@@nerd1000ify 🙂 yes, leaded fuel and added oil in the brun. We obviously didn't know better then. Fun fact: Each avgas airplane, small ones, not turbines, they all still use leaded gas, go check that out. I was amazed that they haven't changed that up to today, I guess the certification issues or old engines that were not made to use unleaded. Did you know that fact?
There is a very specific reason a square four is advantageous for a two stroke and that is it allows disk valve induction on each of the cylinders 2:13 6:55 The Kawasaki 750 clearly does not have disk valves
A square eight would be needed in order to have a power stroke starting at each 90 degrees of turn. Thing that a normal v8 engine can't achieve with a flat plane nor a cross plane cranck shaft.
Be nice if manufacturers would get back to designing modern versions of these engine configurations, with computer CAD/CAM, and fluid dynamics analysis and FEA software, and all the high speed onboard computing power these days, it would be easy to design all the flaws out of these things. Not everything needs to be a straight-3 or -4, or a Vtwin, or a parallel.
Kawasaki and Suzuki stuck with rotary valves long after Yamaha introduced reeds. From a reliability standpoint, I have friends whose RDs swallowed reeds, but I've never heard of a broken rotary valve.
@@CaptHollister Rotary valves do have their problems though, and I have heard of them breaking up. They need good lubrication because they rub against their enclosure, and they flip from side to side as the pressure changes. This also means that they need oil injection in front of the valve, or petroil. Reed valves don't have the lubrication problem.
to say that is to show a serious lack of imagination... theres no reason you cant feed between two pairs of cylinder, using say, the crank disc as the valve, or feed in through the crankshaft as done on RC engines, or even a separate rotary valve driven by a secondary shaft... just because noone did it, doesnt mean it isnt possible. reeds arent perfect. one serious issue they suffer from is bernoullis... faster the air flows between them, the more they draw together... primary school demonstration, blowing between two balloons or sheets of paper... and its constantly overlooked.
@@paradiselost9946 You've obviously never seen a Trabant engine dismantled. Someone did it. If you feed between two pairs of cylinders you have two problems: one is a very wide engine, and the other is that the gas has to do a 90 degree direction change which restricts breathing. As for feeding through the crankshaft, how do you intend to get the gas round the big ends? Excelsior actually tried something similar in the 1930s and the power output was very poor, along with needing a lot of lubricant. Bends slow down airflow. Reeds do not work the way you say. There is a single flap over the inlet, the reed is not parallel to a flat surface. Any pressure reduction due to the airflow is countered by the still air in back of the reed achieving roughly the same pressure, so aerofoil lift really is not an issue. The RD350LC produced 47BHP at 8500 rpm, 134BHP per litre. That's not bad for a road bike.
Now that's strange ; the mock - up Kawasaki 750 square 4 shown has a couple of rather ordinary carbs feeding 4 cylinders ( from the rear ) , not the fuel injection stated in you video ... What's you take on this ???
2-strokes lend themselves to wierd-ass configurations, considering you don't have to find a place to put camshafts and a way to drive them or a "normal" valve train... Rotary disc or reed valves take up less space, or with piston port there's no valves at all.
The square four would have been genious if he had made the two cranks 360 degrees. Then he (Ed Turner), would have made a U engine with perfect primary and perfect secondary balance. It would literally have been vibrationless. But alas he went with two 180 cranks and the rest is history.
I had two Ariel square fours,...in California,they were no good in warm weather,they get hot and blow head gaskets,the Lucus electrical system was junk,the power and ease of starting was good,,handling was good,the brakes were fare
My other desiggn your blue water filth riped off including bike not documented stolen yet had few sealf and Allan wraith designed pretty much unlimited not v enjine or inline not a square either one of highest low profile cubic inch not cc ever built document island of man pretty god damn fast other riped off from us 1 was complete but not assembled projects over thirty million us dollars architecture etc
I can't get enough of these obscure engines
This is nothing, I built a Square 7 Desmodromic 2 Stroke Wankel.
I have never heard of the Kawasaki square four until now. Awesome! I can only imagine what it must have sounded like! Good job!
The "Squariel" remains my favourite old British bike. It's not surprising that all the other square 4s on this list are two-strokes. If you want to build a two-stroke with precisely timed input, you need to put a rotary valve on the crankshaft for each cylinder. If you want to put rotary valves on a four-cylinder engine the square four is the only possible configuration. My most memorable ride was when I borrowed a friend's 500 Gamma to race, ehm I mean "ride", down some backroads with which I was very familiar. Being a two-stroke 500 making 95bhp with a tachometer that only began reading at 3000 rpm, you might expect it to be a hard-edged, peaky machine. It wasn't: it was easy to ride fast and was remarkably comfortable.
"If you want to put rotary valves on a four-cylinder engine the square four is the only possible configuration" How do you figure? Two rotary valves would work just fine on an inline 4.
@@crookedaxle is rather limited imagination, isnt it?
can be a drum/disc between each pair of cylinders, can be a separate rotary valve driven off a shaft, could even be form of poppet valve into the crank driven by a cam. with a bit of thinking, one could use the crankdisc itself as the valve...
thinking of poppets, be interesting to see a reed valve replaced by a self actuating one. i keep thinking of bernoullis on reed valves... harder you blow through them, the harder they tend to "suck" together... easily proven by trying to blow between two sheets of paper.
whereas the shape of a poppet valve should tend to force open as air flows faster through it... basic action/reaction type affair...
but maybe i overthink things, lol.
and then i got other ideas im working on and have to leave other ideas behind for later, if i ever backtrack...
The issue with self actuated poppet valves on 2 stroke crankcases is the inertia of the valve. With only at most 1 atmosphere of pressure to open it, the valve spring has to be pretty light, so it can't close the valve fast enough at high RPM. Reed valves actually have the same problem but being made of very thin sheet are light enough to work ok at rpms in the fun range.
@@nerd1000ify use the crank disc to force it shut ;)
and now weve gone full circle and may as well drive it with a cam.
though not having to deal with combustion pressures or temperatures, that valve and mechanism can be far lighter than the regular valve train.
iunno. cant say ive ever seen a twosmoker with a poppet valve on the case...
@@paradiselost9946 Some very old "oil engines" and so forth had them, you can find videos on UA-cam. We're talking stationary motors which run at a few hundred RPM, so for them the inertia isn't such a problem!
The challenge with any idea for an incremental improvement on a 2-stroke is that they're usually designed to take advantage of the 2-stroke's greatest strength: being very cheap to build. So manufacturers probably won't be willing to do anything that adds too many extra parts. Of course if you want to go crazy and just make the ultimate 2-stroke for its own sake you could do things like run a roots blower instead of using the crankcase, use poppet valves for the exhaust so you get uniflow scavenging, etc.
1:25 by sound alone, I would've never guessed that engine is from the 1930's
Square 4 is an excellent package . It makes a 4 cylinder engine with perfect balance , normally the bailiwick of the inline 6 .
The " Squariel " was considered an Excellent machine , but it was prone to REAR cylinder overheating .
That one sounded real nice, too.
@@someonebald2022 . Yes . It did .
shit cooling for rear bank tho
@@hathaway.1166 And for valves.
@@hathaway.1166 . Yes . I said as much in my first comment .
Modern liquid cooling solves that issue , eh .
I need the captions, brother, you've improved greatly in your channel's history, but there's still some words that I don't catch.
Thanks again
Thanks visio racer!! another very interesting video🎉
Awwwwwwe yeah!
Not super often you find something I have absolutely zero prior knowledge of. This is incredible.
This is not to say you dont teach me all sorts of things, Im just a big ole nerd and spent way too much time on the internet. I usually know a little something and learn a lot, trust me. This however is absolutely and entirely unknown to me until just now! Thanks!
Missed you man, hope you're doing well.
ALWAYS LOVE YOUR VIDEOS !!! HOW COM NO NEW VIDEOS IN 2 MONTHS ? CHEERS
Morbidelli manufactured woodworking machinery rather than "ran a woodworking shop".
They expanded into metalworking machines and CNC . They are now part of SCM Group
While living in England in the 70's and rebuilding a T120 Bonneville, I came across a shop called Healy Engineering that let me use their sandblaster. Their main business was re-engineering Ariel Square 4's. They would enlarge the oiling to the rear cylinders to increase lubrication and cooling among other things, and I would be surrounded by 4+ Ariels every time I visited.
My uncle rode an Aerial Square with a Double Adult sidecar. He used to ride the outfit from Birmingham UK to Limerick Ireland, as far as I remember this was before The Severn Bridge was built so he had a very long drive.
It was interesting to see these. Thanks for presenting this content. 🙂👍
Very interesting, I did not know there were so many companies building these engines. Thanks!
im suprsied they haven't made a come-back. If you think about weight distribution and space in FWDs they make a lot of sense.
The good old 2 strokes, aah the smell.
Way less mosquitoes 🦟. You can smell the awesomeness
Just blame the dog or the hippies next door.
On leaded fuel, just to maximise the amount of damage you do to yourself and the environment haha.
@@nerd1000ify 🙂 yes, leaded fuel and added oil in the brun. We obviously didn't know better then.
Fun fact: Each avgas airplane, small ones, not turbines, they all still use leaded gas, go check that out. I was amazed that they haven't changed that up to today, I guess the certification issues or old engines that were not made to use unleaded. Did you know that fact?
@@illbeyourmonster3591 never, I'm a hippy myself 🙂
There was a review of the Suzuki RG500 Gamma in "Bike" magazine. The headline was "Only nutters need apply!".
Only in Visioracer 😅😅 The best 👌
Man oh man! Those 2-stroke 500cc bikes are amazing!!
I think one of these manufacturers doing retro style bikes should bring back the Squariel. Forget jumprope twins, give us a four!
Square 3 and U 3? Ima need a separate video for those, I can’t imagine how those look
Dude, I miss you every Saturday! Please come back!
Yes
Had never heard about this engine.
There is a very specific reason a square four is advantageous for a two stroke and that is it allows disk valve induction on each of the cylinders 2:13
6:55 The Kawasaki 750 clearly does not have disk valves
The Ariel sounds very good
😮😮 U 4 got the motor cycles 🚲 😊 also had the V twin engines 😊😊 OMG 11 9 2O24
0:30 it moved a bit I'm not gonna lie!
Thanks Bra 🤘 u 😎 cool.... Well spoken and accurate.
would seem like poor cooling of rear cylinders if air-cooled?
Potentially, yes. Modern examples of that same thing is Harley Davidson's air cooled inline heads.
yes air cooling has limitations
A square eight would be needed in order to have a power stroke starting at each 90 degrees of turn.
Thing that a normal v8 engine can't achieve with a flat plane nor a cross plane cranck shaft.
Be nice if manufacturers would get back to designing modern versions of these engine configurations, with computer CAD/CAM, and fluid dynamics analysis and FEA software, and all the high speed onboard computing power these days, it would be easy to design all the flaws out of these things. Not everything needs to be a straight-3 or -4, or a Vtwin, or a parallel.
Square 4 is the only way you can make a 4 cylinder rotary valve engine. Once reeds were perfected, game over.
Kawasaki and Suzuki stuck with rotary valves long after Yamaha introduced reeds. From a reliability standpoint, I have friends whose RDs swallowed reeds, but I've never heard of a broken rotary valve.
@@CaptHollister Rotary valves do have their problems though, and I have heard of them breaking up. They need good lubrication because they rub against their enclosure, and they flip from side to side as the pressure changes. This also means that they need oil injection in front of the valve, or petroil. Reed valves don't have the lubrication problem.
to say that is to show a serious lack of imagination...
theres no reason you cant feed between two pairs of cylinder, using say, the crank disc as the valve, or feed in through the crankshaft as done on RC engines, or even a separate rotary valve driven by a secondary shaft... just because noone did it, doesnt mean it isnt possible.
reeds arent perfect. one serious issue they suffer from is bernoullis... faster the air flows between them, the more they draw together... primary school demonstration, blowing between two balloons or sheets of paper... and its constantly overlooked.
@@paradiselost9946 You've obviously never seen a Trabant engine dismantled.
Someone did it.
If you feed between two pairs of cylinders you have two problems: one is a very wide engine, and the other is that the gas has to do a 90 degree direction change which restricts breathing. As for feeding through the crankshaft, how do you intend to get the gas round the big ends?
Excelsior actually tried something similar in the 1930s and the power output was very poor, along with needing a lot of lubricant. Bends slow down airflow.
Reeds do not work the way you say. There is a single flap over the inlet, the reed is not parallel to a flat surface. Any pressure reduction due to the airflow is countered by the still air in back of the reed achieving roughly the same pressure, so aerofoil lift really is not an issue.
The RD350LC produced 47BHP at 8500 rpm, 134BHP per litre. That's not bad for a road bike.
I've always thought a square engine was where the bore and stroke were the same size.
Sweet.
Now that's strange ; the mock - up Kawasaki 750 square 4 shown has a couple of rather ordinary carbs feeding 4 cylinders ( from the rear ) , not the fuel injection stated in you video ...
What's you take on this ???
2-strokes lend themselves to wierd-ass configurations, considering you don't have to find a place to put camshafts and a way to drive them or a "normal" valve train...
Rotary disc or reed valves take up less space, or with piston port there's no valves at all.
Bring back the Square 4s and U-twins!
You should make video about slovakian engine from 2012 with adiabatic cycle .... and crazy eficiency.
TRY 180° V8 COSSPLANE OR FLATPLANE AKA "FLAT NON BOXER 8
The square four would have been genious if he had made the two cranks 360 degrees. Then he (Ed Turner), would have made a U engine with perfect primary and perfect secondary balance. It would literally have been vibrationless. But alas he went with two 180 cranks and the rest is history.
Is Franco related to Giancarlo Morbidelli?
Those were the days.....🙃
I have worked on the squareials interesting but not overly impressed.
I can't imagine doing 290 km/h on an old motorcycle.
Ariel's all leaked from the heads
The Ariels that didn't leak are the ones to avoid.
I came here for motorcycles but stayed to improve my English pronunciation !!
One was a square 4 and had rotary valves????!
Thank god that Kawasaki didn't make production.....talk about UGLY.
I had two Ariel square fours,...in California,they were no good in warm weather,they get hot and blow head gaskets,the Lucus electrical system was junk,the power and ease of starting was good,,handling was good,the brakes were fare
My other desiggn your blue water filth riped off including bike not documented stolen yet had few sealf and Allan wraith designed pretty much unlimited not v enjine or inline not a square either one of highest low profile cubic inch not cc ever built document island of man pretty god damn fast other riped off from us 1 was complete but not assembled projects over thirty million us dollars architecture etc
Please put down the meth pipe and stop using text to talk with your southern accent. No one can read this drivel.
nice gibberish ;) you always write incoherently?
@@Keith-hc9js wow stop rattling off to your talk to text when you're hitting the meth... Lol.