As an old British 50cc and 125cc motorcycle road racer from the 1960s, I really appreciate your videos. I raced in an interesting era when the 4-stroke engine had to give way to the 2-stroke’s superior horsepower. Although compared to the 4-stroke, 2-strokes were tricky to ride with their extremely narrow power band. This necessitated 50cc bikes having 12 and even 14 speed gearboxes, and a usable rev range of around just 350 revs. So it kept you pretty busy! I’m a retired British engineer, ironically living in Oslo! I’m now in my late 70’s, but still very much a 2-stroke fan. Keep up the good work. It would be fun to meet you sometime, lykke til, Michael Leary

A wise man one said, “Easy isn’t worth anything”. Your an inspiration Alex! Thank you for being you!

Love the fact that you crankout videos this much faster theres been like 3 in a weeks time

i'm envious of your calmness, i'd have nuked my entire garage and gone on a 'Falling Down' style rampage...

as someone who solders alot, i feel your pain, i have a scar on my wrist for like 12/13 years now

Just remember if you put a bridge in the exhaust port you need to drill holes in the piston for lubrication and cooling. Otherwise the bridge will heat up more than it should and it will snag the piston.

Test.. break..learn..repeat... What a great project

Just when we think these videos can't get any better, you do it anyway. Fantastic work.

Yes, don't kill a project by trapping yourself in a corner.

Realy like your content dude, its like a childs paradise here, its so inspiring on my own projects. Keep it up!

I'm glad you're shelving the 100% port - we all NEED that thing to sing us it's song.

One can really see the even faster progress you make while working in your garage halftime 😊👍🏼

i am from the smokey mountians in north georgia usa you have great taste in music .keep up the great work thanx from round

You're a legend roughly 2000 dollars for a single cylinder that you designed thats amazing you've put so many hours into research and development I look up to that

Lovely Video, as always! I absolutely love watching you do 2 stroke things, i am totally sure you will find a way to get the most powerful 2 stroke ever!

The quality of tour videos has realy skyrocketed and i love it, keep the good work up, greatings sweden

This has all been done before. The numbers for max port width in a ringed engine are well known. At 50cc you might try to eliminate the ring and go ABC although, the piston expansion rate would be tremendous.

Man i hope you saved all these exact designs via blueprints so one day you can manufacture your own serious 2 strokes✅✅🔥🧡

Run a ringless piston and run nitro or alcohol / oil mix keeping piston cool just a thought. . Cylinder has to be tapered smaller at top and wider at bottom for ringless piston set up ../ \ ..

Your commitment is stellar, there's not many people that can keep motivated to finish a great idea. I guess that's why I keep watching I'm always full of dumb ideas, very few ever get finished.

Yup it's been 3 years.... It would be nice to see you get that thing out on the salt flats this summer

Just because you're addicted to 2t oil, doesn't make it heroin >_>

This is great Alex, I’d forgotten about this project you were working on and it popped up on my KZfaq feed. The last time I seen you on here you were casting the engine. You are doing a great job. I’d love to do something like this.

You work a lot for those videos man! Thanks for the explanations and everything as a machinist I know how much work goes in there and you’re doing a great job testing these things! I would probably never have tried a single port like that without at least the little bridge like you did on the new sleeve because of that weak point in the ring but it really is noce to have someone actually try it! Thanks a lot!

Hey man, love your work. I would suggest making your cylinder sleeve out of cast iron or brass just for experimentation purposes then go with plaited aluminium later. Cheers. 👍

Sad it didnt work out as planner but your face when it broke for the second time is a verry familiair face😂

Awesome stuff. I have been waiting for!! Realy appreciate how things are going!!!!

You’re a LEGEND in the Making Buddy…. Good Luck with everything, I truly love watching & learning more about how you’re getting SOOO MUCH HorsePower out of engines Sooo Small. By watching you work on these Small Engines, I’m learning more on how I can get more out of Bigger 4-Stroke Engines which I work on. I’ll see you again, next time 👍

Your choice of blues music is superb

Hi, I needed to leave a idea for you to consider: You could taper your sleeve and have a tapered hole in your cylinder. Just like a morse cone. This will give you the opportunity to switch sleeves with ease. Clean out carbon from between the sleeve and cylinder, hampering your heat dissipation. Moreover pressing an aluminum sleeve into an aluminum cylinder will not be easy, you run the risk of damaging both parts. Jan Thiel also did this with some cylinders, I do not recall which exactly, but I guess you know his work well ;). I hope you get something out of this suggestion! Good luck! P.s. This might help with timing your sleeve as well. You can fit it, drill a hole for a pin in the top surface of the cylinder, and fit the sleeve even exactly the same every time. Downside will be that the sleeve will need to be very precise in order to get the heights of your ports to line up!

Thank you for your perseverance. This is a wonderful journey to be witnessing 👊🏻

That’s awesome! Keep at it that’s very interesting stuff there, can’t wait to see when you have the kinks out!

Try a bigger ring gap. Had similar problems with a Kart engine. After I extend the ring gap the problem was gone.

oh man I love this guy's work

I too am an old 2 stroke racer from the 60's when we were developing fast bikes from slow street bikes. Very innovating ideas with the captured ring. I ran an exhaust port shaped something like a T. I imagine your exhaust port shape is designed that way for scavenging purposes. Also ran a dykes ring. Too much friction??? Seems a larger ring would be easier to hold with your captured ring system. Also we had a graduated chamfer on the top of the exhaust port that eased the ring in a little less abruptly. Love this two stroke stuff! Thanks.

Wife thinks im dumb for how excited i get when you post new vids.. cant wait to see you on the flats with this engine..

These videos are the best!

Cant wait to see the supercharged version of this motor.

People like you keep the 2-stroke alive, keep up the good work!!!

I know thicker rings aren’t great for power, but I seems like a ring double the thickness with chamfers on both sides would alleviate some problems. The ring/cylinder contact would be about the same while allowing the ring to ramp over unsupported walls.

Fantastic Videos, really appreciate your work and it has given me ideas for my projects. One thing - you may have already thought of this - 100% exhaust can still be achieved by adding the thickness of the bridge to the dimensions of the port width = 50% each side of the bridge.... you could then have two bridges if needed.

You deserve more sub man

Huge respect for your dedication. Keep going. I'm subbed and will keep coming back to watch.

Never give up! The exhaust so large was a gamble but you tried, now you will have the optimal solution 👌🏻 .. I await the moment that we will hear the engine spinning fast!🙌

No, no, ....thank you, for your tenacity, inventiveness and dedication.... cheers buddy ❤️

Can't wait for the supercharge and Rotary valves stuff!

Keep working at it man. I think keeping the single bridge is key to keeping all the flow you need. Unfortunately the ring Gap has to stay up against the bridge. Excellent video I'm a two-stroke fan from the '80s.

I think a bridge may simplify many things. In racing concepts I think making an engine work is a starting point, paring it back down to make crazy power is the second step. Great wishes for the next phase, I look forward to it!

The sneak peak looks a lot like the FST cilinder (Foekema Symmetric two-stroke)

maybe do more than 100%?? something like 200° with one 10-20° bridge in the middle??

The more variety of design you test, the better. Good work so far!

Watching this come together is as cool as the Deathwish truck, the camaraderie is inspiring.

I feel your 'Fuck It' What are your thoughts on running in two strokes? A myth?

It looks like to me that they heat isn't able to get away from The Ring quick enough and eventually melts the ring

Try a ring like a total seal design. Make a ring with an inner lip. Then use a ring that catches that lip to hold the ring in place. It has no gap but is smaller diameter so does not contact the cylinder wall. Now no uneven parts on the contact ring. Contact ring should be very light contact. Almost zero tension when cold. Ring and engine expansion when warmed up will provide proper contact. You will need to pump heated coolant through the engine to provide enough ring seal to start.

Mate your diligence is impressive. Keep up the good work.

It's been 6 months since I told you to add a bridge to the exhaust !

Thanks for sharing this with us. Have you thought about harmonics breaking the ring? The shockwave coming back into the cylinder. I was wondering why it would break at that point? Twice? Could it be a defect in the hole in the ring? Maybe you can try cutting the small hole with a laser. This is very exciting to watch. I grew up with mopeds in the 1970s. All of my friends had them. I had the fastest. One guy had a quicker one because he had it two speed. But I could take him in a mile run. it could run at 52 miles an hour on flat ground. It would go over 60 down the bridge On the way to the beach. I live on the east side of Jacksonville Florida. 13 miles from Jacksonville Beach. It sounded like a bad ass chainsaw. I had a puch engine with a Jawa cylinder and piston. I made a spacer plate out of brass. I took the pedals off and had a piece of 3/4” all thread with foot pegs on it. Straight bars. Long seat Suzuki tm 75 front end. Tomos rear wheel. 17mm racing carb that faced frontward. It was fast and agile but a itch to push to get gas. I would pass school buses going to school. Everybody was like what the fuck. It wasn’t pretty but it looked cool and one day I came home and my mother had given it away. Along with my two Honda motorcycles. That sucked but my dad gave me a 1964 1/2 Ford Mustang. He told me you can’t screw on a moped. And I can tell you that it’s a pretty tight fit in the backseat of a Mustang.

Before I watch. Congratulations! Edit: Thankfully, the words I now live by are written on your wall. You are an amazing example of resilience. Keep going. You have a great proof of concept. All of this work is something that you and all involved should be proud of. Nothing worth doing is easy!

I think the rings push opposite from the ring gap to the pivot. Hole on the ring changed to long hole or bigger. So it moves freely and won't feel stress. Hope you will be back soon. Love 2stroke.

This Norwegian American loves the project. You also share my taste in music Delta Blues.

Loved the video production on this one. The colour and tone were engaging & the blues music was sheer perfection. The costuming department did a great job with your plaid shirt as it really looked great with the overall colour temperature of the video. Your past life: -child care worker- Hollywood cinematographer!

I know it has to hurt to lose the full width exhaust port, but you may yet be able to come back to this idea for a visit later. Something in the back of my head is remembering pistons that were plated in a particular fashion that allowed them to be used without rings. Something about expansion and contraction rates the would match the cylinder closely enough that rings were not necessary.

I've been waiting for this! What size/model carb are you using? You probably already mentioned it. I've learned a bunch from your videos, thanks.

Before you add that sleeve, why not try a standard style piston and ring to see if the port will work with a standard piston. You can always go back to the three piece piston later. Would be cheaper and quicker, just a thought. Love your videos!! Good luck..

Need more guys like you figuring stuff out in sheds Keep at it Bud

I agree to thin of material on the ring at the locating pin you should only need a thin maybe .5 mm wide bridge maybe 1mm thick into the exhaust port just enough to hold it in place

Loving it as always brother 🤙 enjoy and good luck!

Sad to see this struggle but I’m stoked to see you work regardless

Mad skills, I wish I had seen this when I was riding 2 strokes

for the 100% bore exhaust design, have you considered a spiral piston ring design(essentially overlaping, all the way round twice)? with tapered ends tapering towards the piston on both ends during the heat expansion the ring simply slides the edge that is on top, and the edge that is on bottom towards each other but they can never meet, and it should require no locating pin(hence the tapered edges, the piston would need a deeper ring groove, and wider rings I don't quite know how to explain this idea, and I have no drawing skills so hopefully what I've said puts forth the idea correctly, I can't find anyone whos done it before or any designs like it online essentially a piston ring, but the edges keep going around another turn one under one over

Cannot wait for more future videos! Half time in the garage is gonna pay off

I really admire the cleverness of widening the exhaust port (with central crossbar) to gain pressure on the piston during its descent. Of course at low revs the performance would not be optimal, but, I must say, that I have not followed previous videos (for now) and I do not know what comes after ... maybe a throttle valve ... You put the ring in crisis all the same, especially at high / very high rotation speeds (among other things, it is better to make a classic stop :)). I would propose a somewhat drastic and evolutionary / revolutionary alternative solution ... You could take out the exhaust port at gas pressure and just drill a relative smaller round hole with an electronically controlled actuator and valve on the outside (depending on the rotation speed). To it you create a constant +/- intense vacuum (perhaps with a little compressor that you always send to the drain, connected to 'Y'). At this point, the expansion exhaust is not even needed, a straight pipe is enough ... there is no more back pressure and the fresh mixture does not escape. All the defects of the 2 stroke could be removed and its merits enhanced. know, it could be crazy ... or not ...

I would use more than one bridge on the port. Even with the retained ring piston, you need to spread out the load to ensure you don't catch a ring on the edge of the port...even with a good chamfered edge. You will get a lot of ring wear where it contacts the bridge so make the bridge/bridges wider. Good tunes while doing the ring filing :). Huge advantage of going to a case intake is you can eliminate the intake port entirely...which I think you have done already...I still think a rotary valve on the case intake would work better than no valve to keep the flow from reversing.

Do you NEED a ring gap? Lots of oil to start it with a "loose" ring. Maybe a glow plug to preheat the cylinder and then swap in a spark plug when she's good and warm? Coolant preheat too maybe?

Been waiting so long for a start video!!

Keep on going great content 👍😃💯 from Cornwall England

The music really suits and complements the video.

Worked on a competition RX2 motor in the 80's and it just chewed up apex seals at high rpm. Made the single port a "bridge-port" resulting in a crazy increase in engine life. Have no idea what the power loss was because we could not get the single port version to last long enough to get to the dyno.

Nice job, I'm loving it. Damm for that problem about the ring, hopefully you get a cheap new cylinder!!

Nice work. Looks sweet. On a normal engine the rings rotate somewhat during normal operation. Could you perhaps have a system where the ring could rotate but never allow the gap to enter the exhaust port

Glad to see that ear pro. I can only imagine how loud that pipe must be inside.

That supercharger idea is very interesting i cant wait to see that!

love the smell of 747 in the morning. really interesting watching your development. 👍

Keep building, you are a very skilled engineer

I commented that it could break the piston ring and also the low pressure on the crankcase. I hope to see the engine soon on the dyno!

One of my big issues has been wristpin circlips popping and that piston helps here too.

I been there. When wide ports failed or resulted in poor ring life I shifted a bridged exhaust. When that also gave me heat transfer issues (being an air cooled engine). I finally landed up with 3 ex ports. One main and two aux.

Surely the locating hole in the piston ring needs to be sufficiently inside the inner circumference of the ring itself so you have the full width of the ring all the way around and eliminate week spots like that as from what I can see the hole intrudes into the width of the ring as it is now. Hope this helps.

A sensible move to drop the bridgeless port idea, you have chased your tail on that for so long and nothing so far has proved reliable. Keep up the good work, Kia kaha.

Just a thought but if you put two or three bars in the exhaust port then you can remove them if you think you have too many. Easier than having to add if one is not enough.

LA sleeve co in California will make you whatever sleeve you want, at least they used to, even aluminum or Mag. It’s been probably 15 years since I’ve done that stuff but they were great to work with

Looking forward to the next 4 stroke video!

I admire your tenacity!! And humbleness.

3 years I was just thinking at the start of the vid how long has it bin sins the start on this epic adventure..I was at the start and I am still waiting..

Use steel alloy rings with a circular ( or tubular) section ( like an o-ring) Less cylinder wall contact, less friction.

Same problem with my fl350r there wasn't a bridge on the exhaust port, huge recall on the 85 honda fl350r had them replace the entire top end

Keep rocking brother you will get it, I know it's possible, I built a killer weedeater, still fs 76, it turns 14000 rpm, and after 2 years of me abusing it, still kicking ass 33cc I think😎

I love your dedication to this build, I would not have had the patience to get this far... But I do feel like I just watched a movie where the good guy dies in the end.

the creativity continues on! everything leads to further progress, it can't be stopped! time to ponder and chop some more wood for a week? a Zen chopping break haha