Find the Hidden Power P1 - Making Most Powerful Two Stroke. 

I just want to let you know. You owe us nothing. Don't feel you have to get videos out, or you have to get this running right as fast as you can for us. We came here because this is an interesting project and we enjoy your content. Keep up the good work, and a baby step is still a step.

Thankyou so much for getting the insane sound levels under control man! Now I can listen without constantly changing the volume every time you get on the dyno! Glad to see you're making some progress in these last few weeks, even given the lack of sleep, trust me I have an autistic 5yo boy, I know that feeling all too well

"I'm gonna clean up the garage when the engine is running properly." I've never related so much to a sentence in my life. For me right now, it is when I am finished with the rear suspension/mini tubs. Happy to see several videos of progress in a row, I'm sure it feels good. With any luck you'll be able to get some more sleep soon and make even more progress.

Having run thousands of dynamometer tests over the years, my impression upon studying the peak torque and horsepower numbers of your engine at relatively low rpm (12-15k), it strikes me that the scavenge efficiency needed to generate 20+ bhp just isn't there, regardless of attempts to optimize the ignition-timing and A/F ratio. However-I think that you're on the right track by considering the expansion chamber's design. Since the engine never seems to "hit the pipe", you might consider changing over to an old school variable-volume expansion chamber unit that may allow you the flexibility to maintain (or increase) the engine's torque until the desired rpm (20,000+) where the real horsepower resides... Keep up the promising work, we admire your efforts. Note: Please check the calibration of your instrumentation.

Inline fuel filter will show if it’s starving. Also inline filter will give you fuel on tap to get you over ther flow restriction. This has helped me recently. Actual fix was fuel tank restoration an petcock refresh

The holes in the pipe from earlier tests messes with the pipes resonance. Cutting them off and welding a plate on should really help.

Someone who knows more about 2 strokes please tell me if I’m right. He jumps around a lot, I get the opinion that he does not spend enough time on one specific thing learning as much as he can and perfecting that one thing before moving on to another and I believe that’s his main problem with not making real headway. I have watched every video he has made since the first summer of covid aprox.

In 2000 we ran Suzuki 750rr biked in the WEC. We always lock wired the rear brake pads as far off the disc as possible. 2 of the 3 riders were super bike class riders, they didn’t use the rear brake, the 3rd rider who was a GP 500 rider did use the rear brake, he had to stamp it a bit harder than he was used to. We kept the pads clear of the disc for wheel changes.

Thanks for welcoming us back to your garage!

Well this is great. The base timing might not be accurate but at least when timing is adjusted, the engine responds consistently and in a manner that is expected. Also changing the main jet and header extension responded as expected. It seems that the changes to the exhaust port and rotary valve, seals, etc., leading up to this video were exactly what was needed. Looking forward to seeing how the stinger adjustments change the engine response.

Brilliant again. I remember reading about one of the Japanese companies decades ago, used to start off long and keep trimming the stinger back till they got what they want, then kept trimming until it got worse. Then go back and build the length that worked.

Trust me, it is the powertrain, the belt alone takes at least 25% of the cranktorque away!! The Gearbox another 10% on that remaining 75% and of that you have to count at least 5% for the chain. THERE IS ROUGHLY HALF THE POWER LOST ON ITS WAY TO THE DYNO

Too much advance is "pinging" not detonation. Detonation can only occur due to thermal factors, be that high compression (heat) or too restrictive exhaust (heat) or lack of cooling (heat) That said pinging isn't good for the engine but its not as destructive as detonation. Re timing. Density influences burn time and thus advance required, over laying increase in engines speed. So if "over" advancing the timing improves power then you know there is a deficiency in combustion density. Perhaps try some short duration curves of high timing along the scale with the rest of it flat noting where in the RPM range the high timing blocks are giving you a boost or a loss. With that you may get more of a picture of exactly where the deficiency in combustion density lies in the RPM range and work your way up from that.

First of all, great work as usual. The pipe extension test got me thinking: you made essentially the same power, but at significantly lower rpm. That means the torque is a lot higher. Which means cylinder filling is a lot better. So there's either a problem with the pipe, like not enough scavenging effect or too weak of a backpressure wave, or it's a flow restriction. Could be the exhaust, or anything in the intake tract. Although I don't believe that your port area is the problem, but it could be. Or the intake timing. At those desired engine speeds, every degree in the right direction helps. Air needs time to move. Anyway, keep it up, greetings from Germany!

love it when I get a new episode of a crazy man in a shed making a 2 stroke. probably one of the only times I grab a cuppa coffee and relax between doing uni work and keeping the misses happy. keep it up, even when progress is short ur videos are always great.

Heh. You got me right at the end there. I'm glad it's going well for you. Now you're into my teenage memories - Messing with the EBE050 to squeeze power out while spending as little to no money possible. Metrakit and Malossi got sooo much money out of me

Here's an idea for a cheap power valve. Cut the pipe at the small section of the exhaust and install a washer welded on a shaft, weld pipe back up, then make a lever of sort and degree of opening to get the variable power balance.

It's always a treat to see your videos pop into my feed. You do you, brother, it's why we stick around.

Uncomfortably in the 10hp range! hahaha. I can't wait to see incremental improvements both small and large. Once you can start picking away at individual and related tuning tasks and see a measurable response it will mean you are well down the path of peak output. Up until now it has been a monumental undertaking chasing different bottlenecks and issues and I get the feeling that you are finally getting some traction here! LETS GOOOOOOOOOOOOOOOO!!!!!!!

I just love this guy and the crazy inventor vibe 😂

im glad to see you so exited! and the engin revs like hell :)

I know practically nothing about two strokes, but I wanted to spitball this anyway. what if you made a system that allows you to 'adjust' pipe length/resonance with a computer as a function of RPM, just like the ignition? like having the pipe be a outer and inner sleeve with some form of actuator that moves the outer sleeve to 'lengthen' the pipe

Just love how you experiment things! KEep it up Alex!

100% Alex one clear decision at a time , i would've went the same steps in jetting , check mixture screw too so you have carb flow. Yep as I've always said you'll need the right (longer) pipe for your rpm and hp.

I'd sort out the base timing or at least check it if I was you, really need to know what the actual timing is, if it is actually up at 25 degrees BTDC when the engine is on the pipe then I'd say that you have some combustion issues going on. Anyway, great vid, keep up the good work!

I can relate to the two glasses stack to read small print.drives me nuts😊

Video production is looking great, good job!!

I’ve been waiting for this! (I eagerly await every episode) 😂

Seeing runnjng this engine is always a pleasure ❤

I believe Jennings mentioned maximum timings of around 24 to 26 degrees so it looks like you are spot on the money, it has to be exhaust now out of the major parts it can be , keep up the good work I'd call this one a win

you should get CPI to make ya a bad ass cylinder. I love all the different approaches you take to this thing..2 strokes for life.

Genuine question. How come you don’t test this engine separate from the drivetrain on its own test jig and dynamometer? Remove all variables or as many variables as possible to make it easier to pinpoint issues and extract everything you can from the engine.

Coming from over 15 years of tuning, don't focus on a number on timing. If you have a dyno, give it what it likes and don't pay attention to the actual value. Just check the ground strap of the plug after a dyno pull with a fresh plug. You want the annealing line to be dead center of the bend of the ground strap.

It would seem that your restrictor is also working as a reflector that can change the sonic pulse gate position drastically.

From what i have seen in this video is that the exhaust port is past the maximum surface area which isn't optainable with a oval port but is with a butterfly port at its max with and the diameter at the beginning of the exhaust is what i think way to small because with al the racing 50cc the beginning is mostly arround 28mm but you do great work and i love watching your stuf, keep up the good work

I totally get "old people"!! Lol. I wear two pairs of glasses so I can see up close details all the time! You are not the only one.

It's interesting, the quality of the comments you get indicate the appreciation of your effort.

Love your video, I've been watching since the beginning of the channel

If the cylinder isn’t filling as much as you think it should or is lean, due to the stinger or the carb, the much higher timing numbers make sense to my limited knowledge. Also, the ending got me! But really take your time, we’ll enjoy the videos whenever they come out

You take determination to a whole new level. Bu that's what it is going to take to get there. And you will.

I wonder, just for the heck of it, you talked about and we have seen how fuel can foam up on this engine, if running a pressure pulse style fuel pump can ensure fuel flow is consistent and fuel isn't foaming up or will have the ability to foam up in the bowl. It's like the rotary valve vs reeds, you eliminate the speed of gravity or other factors to do the work but instead introduce a forced factor to ensure things are working as they should be. Either way, keep up the excellent work!!!

Put a barrel valve on the end of the stinger/tuned pipe to experiment with flow/back pressure

Since you've been working on this project for years, it's difficult for new viewers to gain an understandable approach. There should be a “what happened so far”summary maybe 3-4 times a year.

Cliffhanger 😮 Just like old TV shows except the next episode isn't scheduled just appears suddenly, usually when I don't have the time to watch it right away.

That ignition timing looks right to me. Saying it looks like the completely wrong numbers is so funny. The numbers are right because your getting the peak output.

you got me with that last one ^^

two things ... put a pump on that fuel line - as this will make the flow steady, the carb have a cut of valve to protect against overfilling. 2nd - please add a airbox to it... it might sound counter entuitive, but imagine this; the carb actually mixes the AF in front of the carburator and the oscillating effect of the air of the engine is helping to mix the fuel in air..... not this you can harnish by adding a box with the right size to match RPM - then the resonance will help accelerate fuel and air into the engine at right RPM ... at but like the exhaust side....

It would be cool to see a test drive, to see how amazing this engine runs

The exhaust port is two small. It need be tapered to any shape, because you are creating back pressure, where the chamber is suppose to do that at a specific time.

Put a velocity stack on the carb, you need one, it will help make fuel delivery more linear. EGT is a good indicator of correct timing, you’ve got the sensor already, you should use it. Maybe a fan will help your youngest self-soothe at night.

Bigger powerjet nozzle, dual stack carburator inlet trumpet... Gelps rigen higher rpm.. and inlet trumpet helps mid and higher rev range (smoothen intake pulse)

Just awesome that you're back to testing! Please fix the rear brake, though, so that it doesn't get in the way and cause something else to fail. It shouldn't take any time at all, and then you'll not have to worry about it. With the software you're using, can you annotate each run with notes? Or maybe keep a notebook right by the keyboard so you can jot down the parameters for each test? I was *so* happy to see you back to changing one thing at a time for each test. You'll make much faster progress that way. You're frequently battling the question of timing and RPM measurements; I'm wondering if a different approach would work better, like maybe a phototachometer? Might also be worth devoting a small camera (gopro, webcam, whatever) to record what's happening along the fuel line feeding the carb and the sightglass, if that carb has one, so you can tell if there are foaming problems. Someone else pointed out the vibration in the drive belt -- that's got to be lost power in addition to the friction from the belt.

In the Piaggio Ciao the gearbox is in the rear wheel, you can vary it and drive it with one belt and you winn 4 PS

Keep pushing!

maybe connect a sight glass to the carb bowl drain to verify it's staying full.

Thanks woob

PIP , PIP , HOORAY ! 😅 Good morning pass the whiskey please .😊

Put a valve on the stinger and see if it runs better with some restriction. A ball valve or gate valve. Instant results.

May need to test the cylinders on a flow bench 🤷‍♂️👍

you should run several power curves with fixed ignition for example 16, 18, 20, 22, 24, 26 deg. Then put all the graphs together in one picture and then find the best spark advance for each engine speed....after that you program that curve in your ignition system and take another power curve on the dyno

i made the suggestion about the stinger a couple of vids ago,i think it's to big and/or to short,so this will be interesting to se

If you suspect fuel starvation, you might have to increase the size of the metering feed check valve in the carburetor.

I had a similar running issue where after long periods of low load it would stall when i would get on it, turned out my fuel lines were letting air bubbles into the system and starving my carburetors

on this transfer theory, remember this when you add the charger back on, you could increase the transfer and intake velocity to overpower the exhaust port sucking too hard for NA

Dude....................... the cliff hanger..............seriously?!!! 😱

now offset the crank 9 degrees from the centre line ! AND an injector . AND a port height timing cam.

That run that nearly doubled HP, it even sounded much better, more healthy! Going from barely 5,,HP to nearly 9hp. And all the losses there must be close to ,,30-35% more at the crank.give. the engine its own 6speed transmission. And it should really wake up.. seeing it with boost would be soo interesting!!

What is the goal of this channel. It seems like a never ending project that just stagnates.

Have you considered getting yourself a banks data Monster ? You record all of your fuel pressure data ( add some sensors ) and egt temps etc onto a sd card. They look very good. ❤

i think the chain may need to be tightened and may help things , looks like it has alot of slack

What about 3D printing or milling a clear carburetor bowl to monitor that there’s sufficient fuel? Only needs to last long enough for you to rule out there being a fuel issue there. Keep going. Love your fortitude 😊

Have you ever thought about getting an exhaust gas analyzer?

Let’s see how it behaves!!!

Good to see small changes, change something then go back to best run settings, there should always be a "happy setting" that you can return to, that old test pipe is looking quite sad maybe build a new TEST pipe with more adjustability in mind, modular design

I love seeing this ❤😂

With regards to your assumptions about the flow relations of the transfer and exhaust ports and the combination with the stinger pipe, my advice is to contact a CFD expert from your local university. Give them the CAD geometry and some parameters before spending years and years fiddling around. Some mathematics can solve most of the issues :)

1. Try any other pipe just to see gow it behaves. Slap on the Yazuni and test! 2. Add some mass to the carburetor to see if it helps vibrations! Like ziptie a steel piece to the body of it tight. 3. Take a day off 😂👌

The fueling playing up after longer held throttle positons, sounds alike fuel frothing in the float bowl, or in the lower end of the fuel feed pipe into the bowl. This could/might potentially be solved or reduced with a light spring, or two, inside fuel feed pipe, (a pair of small diameter stainless steel springs from a click-pens & retractable ink biros, one to fit inside the other, and both to be loose inside the fuel feed pipe, ..or small part/piece of a metallicised dish scrubber cord/pad,) ..to create a more partial-turbulent flow within the feed pipe, near it's entry into the bowl, to reduce fluid flow stability for bubbles to form; but you might need to double up the fuel feed lines to meet the rate required, with the anti-frothing spring or metallicised pad piece inserts. Or by having a greater flow rate or larger diameter pipe & thus head pressure to counter the vibrational resonance that lessens fluidic gravity to form bubbles, of a combination of larger main feed pipe, and a springs turbulator insert. Then again the potential 'frothing' could also, also be down to vibrations from resonance in-balances of the 'double motor' two cranks crank balances, and their secondary forces combining at some points in the rev ranges assisting in inducing frothing during longer held constant throttle durations.

I’m not a 2stroke guy but has RPM increases you have less time for combustion so generally you want a little more ignition advanced now all this greatly depends on how well the cylinder is filling and engine load

equal power at 3/4 or possibly 1/2 throttle makes me think crank seals got beat up after the hot runs before you redesigned the rotary valve. smoking gun would be the pipe and exhaust in general, Id say it would be absolutly top priority to properly remove the accessories on the pipe. Ive been thinking, it might be adventitous to fab a guid rail to secure the leading edge of the rotary valve blade, to prevent lateral oscillation especially at high rpm. It could very well be beffeting with the forces at work is there a method to monitor peak case pressure during operation? 🤔

What fuel you using, nitro methanol? Model engines seem to make lots of power for their displacement, they also have unique transfer ports. Usually lots of em, bridged, and run all the way around the cylinder except exhaust port...They run the intake charge in through the little end of the crankshaft, which acts like a rotary valve. Enjoy your vids, keep up the good work.

I always wonder if part of the issue is just a simple exhaust leak? It's losing the effective pulse

Shorter stinger = more torque, Longer stinger = wider, longer powerband so power for longer.. Thinner stinger same length might restrict too much Man i love these series so much! used to have a Derbi Senda with the EBE50 engine, managed to get 14bhp out of the 50cc i had, then blew it up.. upgraded to a 70cc metrakit, which blew a headgasket and hydrolocked, breaking the innerhead and bent my crankshaft... Then experimented with a malossi MHR team 80cc ( Bad bad cilinder btw ).. In the end, i went with a cheap ass Airsal 80cc, completely changed the geometrics inside, managed to get 23bhp out of that and called it a day, custom made exhaust etc all calculated. Man i had such a good time working on this, eventually sold the engine to a guy that now uses it for classic races in a classic Derbi GP bike.. He topped it out at almost 192km/h on the TT Circuit in the netherlands, was amazing

On this episode of 2StrokeConfusion...

Seems like you need more data. What sensors could be added? Exhaust temp and mixture?

NOOOOO! I need to know, did the stinger help? LOL

110 kph on 50cc puch is the record i made fucking with compression ratio's and racing parts, love to try your solution.. 20k rpm is like nuts.

I didn’t go through all the comments yet but had to mention the timing. You should be increasing timing as rpms rise. The piston speed is increasing but the flame is not so you would need to advance the timing. I’m sure you got base timing right as you had a dial indicator on it and set it. Also maybe make small timing changes like a few degrees and not a 5 degree jump.

I am here for the madness.... that is all ;)

Good luck 👋

hope you calibrate the dyno using stock motorcycle Bhp, i cant sure to see the accuracy of that instrument

very cool

Would the increased timing also result in a lower temperature in the pipe, thus changing the effective tuning of the pipe? The speed of sound changes as temperature changes.

Can you add a valve to the stinger to change the dynamics of the pipe, like a exup the yamahas used in their 4 strokes. Im sure there is reason this is wrong, or been tried before. Like its a restriction. Or a variable size stinger outlet that doesnt use a butterfly. Just to hep the engine to get higher in the rpm where its supposed to make power. Or even a motor to spin the pip motor past that fall off at 18k and into that 22k sweet spot. Yeah im fairly adhd, just thinking outside the box. 😆

Sounds like running flat at high rpm .. or not enough timing

Have you read the timing on the plug recently?

Hi there, have you seen the liquid piston rotary engine ?

yep it gets fuzzy

Could someone, please, explain the timing curve to me? When I learned about engines outside stonehenge, I wasn't allowed in, the shame-an told me that ignition should be at or even after TDC to prevent kickback when starting and then advanced it to ignite earlier with higher RPM to give the flame time to do its thing, because the fuel burns with the same speed nomatter the RPM.

Is the purpose of the expansion chamber to create a higher (than atmospheric) pressure area for the exhaust gases to aid in pushing back exhaust pressure towards the cylinder?