Finally, I think our 2stroke suffering is about to end! 

I don't even care if we never see the results we are all hoping for. I love this channels content... You could be clearing out a cat litter tray for all I care you would make it enjoyable 😂😂

I love the fact that you don’t hide the failures, this is why I watch your channel.

MY GOD MAN!!!...Over the years I have written you about this project (in depth) several times!!!...Your reinventing the wheel approach to such a complicated mess of factors is infinitely impossible!!...The FIRST thing you need to buy (or make) is a "flow bench"!! ..With your love if small detail, I know you will enjoy it!!..This is the ONLY way you can make so many small changes without all the machine work and time you spend building parts!!..All these changes (Ramp angle, port size and diameter, etc. etc).can be figured out mathematically. Buy the operating manual for a "Super Flow" flow bench!!!!!...It has all the formulas for this work!!..You can then "time" your "pulses" for intake and exhaust to maximize your efficiency!!...You can make ALL your designs out of plastic, etc. and then copy them in metal when they work 100%...Please buy the manual (it's cheap!)..It would have saved you YEARS of time and you can figure out EXACTLY what the lengths are from the tip of your velocity stack to valve, along with sizes and shapes!!...Once you read the manual..you WILL understand.... This is from a 72 year old Race engine builder for any kind of performance engines...Love the channel, just hate to see all your time and effort spent, pissing jnto the wind...👍👍👍🗽🇺🇸

Longer and bigger exhaust pretty sure that's a big one of your problems🙂 from a dragracer on 2strokers.. May the speed gods be with you😁

So glad with all the progress with the engine have been following for a couple of months and the small progress made each week is so rewarding

An egt would give you a good idea of where and when you’re having fueling problems. You’ve already have a thermocouple on the sparkplug, add another to the pipe. It will make your experiments less frustrating.

Try adding a spacer to your pipe, increase the header length 20-30mm and see if it'll pick up in the lower end some. You've changed so much, but nothing with the pipe.

sheesh what an emotional roller coaster of an episode... I am glad you found and started to eradicate some bugs. well done and love your work keep it going 👏 👍 💪

I think it is because all the cool stuff is missing, like supercharger and double rotary exhaust valves 🙂

Great work! This is. A good first step for more systematic logging. You could log: intake manifold pressure and temperature and probably also mass air flow. Also exhaust pressure and temperature. Would make it much easier to actually get a good idea what is hurting performance and qualifying your guesses more :)

I've enjoyed your videos for a long time, but I think this video is a good showcase of not only your strengths, but your weaknesses too. I don't think your workflow is incremental enough, and you're likely overshooting the sweetspot because of it. Just try varying one thing at a time, back and forth in small steps, to really narrow down where the sweetspot is for every part of the system. The position of those sweetspots will change, so you'll have to circle back and adjust everything all the time, but it's the only way you'll ever reach the extreme performance you're aiming for. It's not about mining for ideas, hoping you've come up with the solution, worrying that it won't work this time either. It's a way more relaxed mindset. It's "let's change this half a degree, and if the dyno numbers improve, change it half a degree more." for a long long time. That's where the horsepower is.

I love your enthusiasm and dedication to the engine. I've been working on my race car for 22 years and still love every minute of it

I cherish every minute with you. The music while wearing my headphones is so awesome! When you went under the table to sulk I blurt out loud with laughter. It was encouraging to see it pull through a couple of gears at the end. I built 3 honda MB5's with stock CR 80 engines with Dave Miller expansion chambers on each of them and your bike on the dyno brings back so many memories/sounds/and speed! Keep it up!

I just love your extremely droll sense of humour, your skill and your vision. All power to you - and hopefully some spillage onto the dyno numbers. My favorite channel.

He’ll most probably get there in the end, but personally I hope it’s a long time from now. Because shamefully I enjoy the roller coaster ride of failures and successes. Yes I’m a glutton for punishment and I love this channel, lol! More please👏

It was hard seeing you so beat down, luckily you found a way back. A true roller coaster as somebody else posted! Keep up the good work and never change!

Doing one change at each test is definitely the way to go. Takes more time, but only then can you determine what works and what not So glad to see how your channel has grown. Well deserved!

Your a good engineer. Keep up the good work. The fun is in learning and experimenting. Best part of the whole experience. Your on the right track.

By far my favourite and most inspiring channel on RU-vid!

I think the journey of finding what it isn't has been much more enjoyable than if you were to just have gone straight to this. Looking forward to some success! You're the rob dahm of 2strokes ;P

Always enjoyable to watch whether up or down, winning or not quite winning. These videos give me encouragement to persevere with my own projects when things don't go well.

Your smile at the end of the video, after seeing a lot of progress with the exhaust, Made me very happy. Keep the hard work, hope to see big figures in HP the next episode

Back to basics is looking good, the exhaust port and chamber fillers have made a difference, I'm hoping we see the brute force concept come back into play now. ANOTHER GREAT EPISODE 👏👏👏

Your videos are not only entertaining but also very educative, I've learned a lot from you!

You are my favorite creator. I enjoy every single video you post. Your camera angles and video quality are the best no one touches your style buddy please continue doing what you're doing. Congratulations 🎉🎉🎉

Im so happy to see this revent breakthrough ive been following this channel for 5+years and the journey has been wild

What make me come back to your channel isn't the fact that you fail, it's the fact that you keep trying.

Mr 2 stroke I've watched you for ages an I admire what you do ... in times when you feel like giving up just remember if it was easy everyone would be doing it .... aswell once apon a time everyone thought the world was flat an who ever said it was round was crazy you sir are a innovator to the 2 stroke world an when you finally crack the code your be written in books as a legend not a crazy mechanic in his shed !

Your exhaust port may have equivalent area to your port area, but due to that extremely thin oval shape, it will be *effectively* much smaller because of the boundary layer of air that forms where moving air touches a stationary surface. For some reading on the subject, you can look at things written about the flow of oval-shaped exhaust vs circular. An oval shaped exhaust of equivalent area to a circle will flow less, because more of it is in the turbulent boundary flow area. I have limited 2 stroke experience, but in 4 stroke engines the optimal exhaust port shape is like a D, but with the flat part on the bottom and the curved part facing up. Porting the bottom of your exhaust port so that it is flat, and the top is the original oval shape, would probably significantly improve exhaust flow. I see you came to a similar conclusion on your own in the latter half of the video, but I wanted to try and explain some of the mechanics behind that in case it might help you later. In 4 strokes at least, the step going from the exhaust to the port is generally a positive thing. There are even headers that have an additional step-up in size. If you can with CFD, maybe calculating the area of your cylinder ports minus their boundary layer, and making that equivalent to the exhaust port minus the boundary layer? You deserve the positive results man, and I'm happy to see it. As a viewer though, the journey is just as interesting as the destination. Is it just me, or does it sound cooler with the big exhaust port?

Imagine how many cylinders, heads, reed blocks, Carb variations, exhaust angles and lengths. Yamaha, suzuki and honda went through in their 2 stroke racing days. Love the Channel, love the thought process. Thank you for sharing.

23:10 - your face says it all. The suspense builds once again. Your videos are so enjoyable to watch, thanks for another quality episode. See you next time!!

Trial and terror!!! There isn't any other way 😂 Super action packed episode 🤙 Love your drive and stamina, we're cut from the same cloth 😜 my 71 x 62 241cc took me over 10 years of struggle. It's worth it in the end, I jump on it, and it rides like a factory bike on steroids @12,500 rpm. I really don't want to have to pull it down anymore tho 😂

This video was epic and brought joy for me. Thank you for this video!

I have gotten very bored of RU-vid. But this channel always keeps me at the edge of my seat. Awesome job man!

Great job Alex. This is a breakthrough moment. The salt flats are calling. Cheers from Morrison, Colorado.

I had this Koiritz twin two stoke engine made in 1976 apart and was looking at the intake transfer ports and the angle at which they shot mixture into the cylinder. The left and right A intake ports were the widest ports (about 3-4 times wider than the B and C ports) and would push air towards the backside of the engine away from the exhaust port while the B and C ports which were about the same width looked like they would help move the mixture upwards into the top of the cylinder and help tumble the mixture coming from the A transfer ports. This engine ran without a pipe on it. When I was looking at this old engines conservative design (55hp from 440cc) I was thinking about your radical port areas and how much you rely on exhaust pulses to keep the mixture in the cylinder. Neat to see this idea of port direction and size being explored again.

man it sounded sweet sat at 14k rpm. this channel has been one long evolutionary learning process. good going dude.

love this channel. You learn something new every video

The under desk retreat cracked me up... "I'm just going to lay here now and wait for the sweet release of death" 😂

Sir you are an artist, a thinker and a doer. Cheers to us all

I would like to see the deathtrap on that dyno again at the start of a video so we can see the power it makes as a reference, I feel like this has taken a big step back from the early days of the brute force concept engine, that with the single rotary valve seemed like the best version in my opinion

Thank you for the amazing Videos!

Great episode, sounds so much happier after the port opened up. A useful stepped edge is a useful step

It truly helps me understand why I buy R+D designed stuff and 'proven' things for my engine (4 cyl. car engine) because WOW the differences here are soooo small, yet make SUCH a huge improvement. The R+D and Trial and error is what you are paying for when you truly want to just 'build something good first time'....vs all R+D yourself.

Sounding much better than the last time. You will work it out. 👌🏼👍🏼👍🏼👍🏼🤙🤞

i love my fridays coming home after a long day and watching you videos has been apart of my rotine for a long time now

From basic pumping physics that stepping you mention will create turbulence losses and I think also affect the resonance frequency of the exhaust pipe. From speaker theory I know that a tapered tube which is constrained at the end it acts as a longer tube. Think Voight speakers.. I think turbulences losses have the same effect as a volume change losses in this situation, so I would bet that a smooth transition would work the best. Cant wait to see the next vid!

Keep up the perseverance! You will succeed!

progress in the right direction now, I AM HYPED FOR NEXT EPISODE!!!

So much hard work! Love the content

Opps...too much coffee...article is a year old...lol...but good summary... Alex, you are on your way I like to cheer you on in Utah when you return. I lived in SLC 1981-1983...my bikes at the tine 1979 IT-400 and 1970 Yamaha 350 R5...buddy drove new Husky 1982 430 WR....then broke his leg... I kept up but the Husky was faster. We rode once towards the flats...lots of wide open area to get the wick up and all the way open. Once I went to Draper...thru the back way...too cheap too pay...went to the top to witness Widow Maker hillclimb. Two made it over in 2 hours... How did I get the bike there ?...I hauled using a 1965 VW Bug...powered with my built 1835....another story...lol. The bike was strapped to the rear bumper. In that VW, no one could pass me going up Parley summit hill on i-80...lol This will be the end of my rambling... It's all good

Would like to see a road test to see what it does off the dyno.

it's so nice to see that little smirk back on your face again mate that's the spark the little ember back there flaring back up for the first time in months

Good to see a smile at the end.

17:58 Sometimes, this is how I feel waiting for these videos... Please keep up the good work!

The angry wasp is starting to scream. Soon we will all want one!

Keep at it. I dont mind the results or making a ton of power. I just like the fact that you try new things with 2 strokes when no one else is

Your my 2stroke hero!!!!! Thank you

I really liked this episode! At least you are willing to re-examine your theories.

I think you need to do one of two things. Adapt the aprilia cases, that you engine is coupled to, to verify your cylinder, or, put a known good cylinder onto you cases. This way you will know where to start looking

Great video. Amazing actually. Great wrk. Always enjoy watching

Another brilliant video with very promising results this time .

Always a real pleasure to see the progress here 👍🏻 I think you need a shifter to avoid the power loss when you’re shifting gears.

Here's my theory. There's a reason exhaust ports are not normally so flat. The walls of the port create turbulence within a certain distance of them as the exhaust gasses try to cling to them. It's caused by the friction of the gasses as they flow down the port. The further you get from the wall, the less turbulence there is. So if your port is quite flat like yours was, there's more turbulence almost everywhere in the port compared to a rounder shape.

Great work 👏 well earned progress

Lekker to see you emerging from under the desk and getting some promising results!!!!

The only thing that I can think of is maybe a clear coat of the pla stuffers. At high rpms, it may be pulling air right through the print. I do some printing, and it is usually not waterproof.

How about adding a simple wideband lambda to see how the engine is running? This would give you a great insight into how the fuelling system is setup

AHH man, you got me waiting and hooked for the next installment.

New name for the channel "2 Stroke Suffering" 😁😁😁

Great show been seeing all of them mit check a carb you mit like its calleda smart carb sc2 thats what its called have fun great work thank you...

Exciting progress!

Nice to see and hear PiP doing so well. The only thing I have left over from my engine tragedy is the 28mm carb which has larger power jet fitted made from a 5mm round jet. This ran very well, I even fitted a large pilot jet which I used as a fine fuel control at high RPM. If you want it and want to use it, it's yours. I fully understand your sentiment re not just wanting to tune a standard engine. Please, tell me what this music is you used. PS, it's the old adage. You have to get it out quicker than you put it in. PPS, would you ever consider blocking the B port ducts with toilet paper and just try running it on the A ports. Your getting there!

🥳 good job mate 🎉

Yaaaaasss man!! 👏🏼👏🏼 finally! Good job

I love all the fun and nonstandard stuff you do dont give up on your non bog standard way of doing things that is where true advancement and true boundary pushing resides at

My heart sank when you started running the engine after the transfer channel mod. But seeing the increase in HP after the exhaust mod im happy you got some part of the smoking gun. I love this channel for the exploration/ trial and error! Keep it up!

It’s important to try an idea until the end to found the limit and go forward !great job dude !!!

That thing sounds awesome now! Good job brother

I love your efforts and showing these lessons. The velocity of air at a port wall surface is zero and increases exponentially away from the port surface. Its the boundary layer effect. You have on those wide skinny ports an overlapping boundary layer with near zero velocity for much of your port cross section. So what I'm saying is you want the most cross sectional area with the least amount of port surface area. Perfect circle my friend.

Definitely need to revisit the exhaust. For any 2-stroke engine that you want to run at very high RPM, the pipe diameter should increase into the expansion chamber at a slower rate than the decrease back to a smaller diameter happens. This is especially important with this engine, since the piston vs crankcase volume ratio and compression ratios are both expected to be much larger than typical.

Very nice! From despair to hope, what a ride 😂👍

Best channel on YT ✌️

Very entertaining dude. Keep chipping away with this setup and you will get there buddy. Big jumps in direction is causing too many grey areas I feel.

Your reaction at 23:10 is just amazing to watch, it seems small, but man that gives hope!

I’ve said it before and I’ll say it again- my favourite RU-vid channel.

Your air compressor was trying to to tell you something... make power and make it loud, not compressed air coming out of a small port. Please keep the videos coming, love them, Cheers.

The gentlemen that mentioned the use of an see through cylinder head is got a good point, because if you can adjust the actual flow pattern, and see how much it changes the power curve. Then adjustable vanes in the intake that allow you to curve the airstream to the optimal position to increase the flame kernels to work to your advantage. This would also give you a better idea of optimal position for the spark plug location in the cylinder head itself. Also you can actually play with different designs for the combustion chambers like they do with cylinder heads on automotive designs. Such as the hemispheric head used by Dodge, are different designs by the other engine programs like Honda indi engines, the options are unlimited by examining many different types of combustion chambers, because although the two cycle engines are unique in a way, but there's been so many different changes over the last few decades that unless you try to open your mind's eye to all the different manufacturers designs your trapped in a never ending circle chasing your tails

In the intake duct works an inward-contraction duct, and the exhaust duct acts as an outwardly expanding duct. Hopefully Google translate made a sensible translation, this too needed to be corrected.

I built a few Chevy motors as a kid so did lost of buddies, we'd put on big holly carburetors on and they do what they'd do...however, one day instead of the the big holly carbs #holly750/850 double pumpers ....one of my buddies used a couple of small Carter carburetors...the performance was impressive.... if that gives you any ideas idk...just throwing it out there! Keep up the awesome work man!

Svorsk her, I'm the one who won the signed whiskeyglass btw. Started watching your videos all over as me and my best friend bought our teenage mopeds now att 40 yrs old. We started our competition all over only with a grown up budget. I see so many faults with all cylinders I look at, now that I know what to look for. BTW, next time you travel from Gardermoen, I can offer free parking and be driven to and from the airport as I live minutes from the terminal. In exange for some 2 stroke knowledge of course hehe. Just pm me if your interested. This video was really interesting as you got to try so much so we could hear difference in response and so on. I replayed the first half of the video several times and I felt you had a "breathing problem" and as I watched the next half I felt I was right. If I were in your situation, I would remove the crankcase filler and raise the needle. It seemed to respond the best then. Love the rpm, looking forward to the next video to find out the solution.

I'll keep watching, no matter what

Another thought. Barrier gases on exhaust duct due to narrow height. Turbulence near walls so you get Eddie currents on narrow passages, so even if it was 100% of exhaust port it wouldn't flow like a round channel. Yes exhaust

Good show Bravo

Yesss best time of the week again

How about a plexiglass cylinder head and a smoke machine to blow smoke through the crankcase so you can visualise how the ports are directing flow?

22:25 many four stroke exhaust headers use the step feature, its called an anti-reversion step.

Honda GP Barrels , you change the step length of the oval step to round transformation with different fuel and exhaust pipes !

So hard to see you struggling trying so hard for your ideas. Keep going my friend the solution may seem impossible but your engineering logic will prevail. Nobody's tried harder than you. Everybody who follows your site wants you to succeed Take care matey look forward to success if anybody deserves a victory its you Arthur

Try beginning with a model that really works! After years immersed in 2 stroke mods, it makes sense that you could create a new model from the ground up, unfettered by the limitations imposed by mass production & commercial factors. HOWEVER, in spite of your years of experience and deep understanding of the factors involved, seems to me the the exquisite complexities of the 2 stroke have so far defeated your best efforts to create a basic reliable model, in spite of intelligent and exhaustive tinkering With all due respect and sincere appreciation for your efforts, I cannot help but think that the latest strategic shift to a pip, starting simple and proceeding step by step from there was not radical enough. Seems like you are getting mired in the old process of tweaking this and that variable - intelligently but without much success. Why not start with a model that has had the benefit of years of experienced engineering knowledge and long hours of iterative model tweaking and dyno testing. AND MOVE ONWARD & UPWARD FROM THERE with the improvements that occur to you. IMHO the 2 stroke process involves a chain of extraordinarily complex and nearly inscrutable fluid dynamics the optimization of which can only proceed from the established rules of thumb and from then on a trial and error basis. Tho you may have to give up the dream of starting from scratch, evolving from the known rather than from a revolutionary start might lead to the revolutionary end you pursue. Tho you have good reasons to avoid an EFI system, is it possible to get more sensors involved to monitor temp, pressure, exhaust composition, fuel -air saturation, et al? Without knowing more about the process parameters, seems to me you basically make an educated but uninformed guess about what to do next. Finally, I want to add my appreciation to that of your many fans for sharing with us the day to day process, ups and downs of a man creating a machine. Your seat of the pants creativity and perseverance in the face of the trials experienced are not just enjoyable to watch but inspirational for all of us who tinker with the real materials of life -- in garages, tool sheds, and basements the world over. THANK YOU!